diff --git a/esphome/components/api/api_frame_helper.h b/esphome/components/api/api_frame_helper.h
index 1acaa6f96e6..98de24501ea 100644
--- a/esphome/components/api/api_frame_helper.h
+++ b/esphome/components/api/api_frame_helper.h
@@ -228,13 +228,13 @@ class APIFrameHelper {
     EXPLICIT_REJECT = 8,  // Noise only
   };
 
-  // Fast inline check for read_packet/write_protobuf_messages hot path.
-  // In DATA state, state_action_() is a no-op (falls through all checks to return OK).
-  // This avoids a 447-byte function call on every packet during normal operation.
+  // Fast inline state check for read_packet/write_protobuf_messages hot path.
+  // Returns OK only in DATA state; maps CLOSED/FAILED to BAD_STATE and any
+  // other intermediate state to WOULD_BLOCK.
   inline APIError ESPHOME_ALWAYS_INLINE check_data_state_() const {
-    if (state_ == State::DATA)
+    if (this->state_ == State::DATA)
       return APIError::OK;
-    if (state_ == State::CLOSED || state_ == State::FAILED)
+    if (this->state_ == State::CLOSED || this->state_ == State::FAILED)
       return APIError::BAD_STATE;
     return APIError::WOULD_BLOCK;
   }
diff --git a/esphome/components/duty_time/duty_time_sensor.h b/esphome/components/duty_time/duty_time_sensor.h
index d9fb2a6d604..d21802ebb6c 100644
--- a/esphome/components/duty_time/duty_time_sensor.h
+++ b/esphome/components/duty_time/duty_time_sensor.h
@@ -41,9 +41,9 @@ class DutyTimeSensor : public sensor::Sensor, public PollingComponent {
   sensor::Sensor *last_duty_time_sensor_{nullptr};
   ESPPreferenceObject pref_;
 
-  uint32_t total_sec_;
-  uint32_t last_time_;
-  uint32_t edge_time_;
+  uint32_t total_sec_{0};
+  uint32_t last_time_{0};
+  uint32_t edge_time_{0};
   bool last_state_{false};
   bool restore_;
 };
diff --git a/esphome/components/growatt_solar/growatt_solar.h b/esphome/components/growatt_solar/growatt_solar.h
index b0ddd4b99d8..833d6a36ddb 100644
--- a/esphome/components/growatt_solar/growatt_solar.h
+++ b/esphome/components/growatt_solar/growatt_solar.h
@@ -56,8 +56,8 @@ class GrowattSolar : public PollingComponent, public modbus::ModbusDevice {
   }
 
  protected:
-  bool waiting_to_update_;
-  uint32_t last_send_;
+  bool waiting_to_update_{false};
+  uint32_t last_send_{0};
 
   struct GrowattPhase {
     sensor::Sensor *voltage_sensor_{nullptr};
diff --git a/esphome/components/hte501/hte501.h b/esphome/components/hte501/hte501.h
index b47daf9157c..7f29885f49d 100644
--- a/esphome/components/hte501/hte501.h
+++ b/esphome/components/hte501/hte501.h
@@ -18,8 +18,8 @@ class HTE501Component : public PollingComponent, public i2c::I2CDevice {
   void update() override;
 
  protected:
-  sensor::Sensor *temperature_sensor_;
-  sensor::Sensor *humidity_sensor_;
+  sensor::Sensor *temperature_sensor_{nullptr};
+  sensor::Sensor *humidity_sensor_{nullptr};
 
   enum ErrorCode { NONE = 0, COMMUNICATION_FAILED, CRC_CHECK_FAILED } error_code_{NONE};
 };
diff --git a/esphome/components/nextion/base_component.py b/esphome/components/nextion/base_component.py
index 86551cbe238..7705b21b0b4 100644
--- a/esphome/components/nextion/base_component.py
+++ b/esphome/components/nextion/base_component.py
@@ -27,6 +27,9 @@ CONF_PRECISION = "precision"
 CONF_SKIP_CONNECTION_HANDSHAKE = "skip_connection_handshake"
 CONF_START_UP_PAGE = "start_up_page"
 CONF_STARTUP_OVERRIDE_MS = "startup_override_ms"
+CONF_TFT_UPLOAD_HTTP_RETRIES = "tft_upload_http_retries"
+CONF_TFT_UPLOAD_HTTP_TIMEOUT = "tft_upload_http_timeout"
+CONF_TFT_UPLOAD_WATCHDOG_TIMEOUT = "tft_upload_watchdog_timeout"
 CONF_TFT_URL = "tft_url"
 CONF_TOUCH_SLEEP_TIMEOUT = "touch_sleep_timeout"
 CONF_VARIABLE_NAME = "variable_name"
diff --git a/esphome/components/nextion/display.py b/esphome/components/nextion/display.py
index 3bfcc959954..b8fcd5d8cfa 100644
--- a/esphome/components/nextion/display.py
+++ b/esphome/components/nextion/display.py
@@ -33,15 +33,24 @@ from .base_component import (
     CONF_SKIP_CONNECTION_HANDSHAKE,
     CONF_START_UP_PAGE,
     CONF_STARTUP_OVERRIDE_MS,
+    CONF_TFT_UPLOAD_HTTP_RETRIES,
+    CONF_TFT_UPLOAD_HTTP_TIMEOUT,
+    CONF_TFT_UPLOAD_WATCHDOG_TIMEOUT,
     CONF_TFT_URL,
     CONF_TOUCH_SLEEP_TIMEOUT,
     CONF_WAKE_UP_PAGE,
 )
 
 CODEOWNERS = ["@senexcrenshaw", "@edwardtfn"]
-
 DEPENDENCIES = ["uart"]
-AUTO_LOAD = ["binary_sensor", "switch", "sensor", "text_sensor"]
+
+
+def AUTO_LOAD() -> list[str]:
+    base = ["binary_sensor", "switch", "sensor", "text_sensor"]
+    if CORE.is_esp32:
+        base.append("watchdog")
+    return base
+
 
 NextionSetBrightnessAction = nextion_ns.class_(
     "NextionSetBrightnessAction", automation.Action
@@ -55,7 +64,24 @@ BufferOverflowTrigger = nextion_ns.class_(
     "BufferOverflowTrigger", automation.Trigger.template()
 )
 
-CONFIG_SCHEMA = (
+
+def _validate_tft_upload(config):
+    has_tft_url = CONF_TFT_URL in config
+    for conf_key in (
+        CONF_TFT_UPLOAD_HTTP_TIMEOUT,
+        CONF_TFT_UPLOAD_HTTP_RETRIES,
+        CONF_TFT_UPLOAD_WATCHDOG_TIMEOUT,
+    ):
+        if conf_key in config and not has_tft_url:
+            raise cv.Invalid(f"{conf_key} requires {CONF_TFT_URL} to be set")
+    if CONF_TFT_UPLOAD_WATCHDOG_TIMEOUT in config and not CORE.is_esp32:
+        raise cv.Invalid(
+            f"{CONF_TFT_UPLOAD_WATCHDOG_TIMEOUT} is only available on ESP32"
+        )
+    return config
+
+
+CONFIG_SCHEMA = cv.All(
     display.BASIC_DISPLAY_SCHEMA.extend(
         {
             cv.GenerateID(): cv.declare_id(Nextion),
@@ -115,6 +141,14 @@ CONFIG_SCHEMA = (
                 ),
             ),
             cv.Optional(CONF_START_UP_PAGE): cv.uint8_t,
+            cv.Optional(CONF_TFT_UPLOAD_HTTP_RETRIES): cv.int_range(min=1, max=255),
+            cv.Optional(CONF_TFT_UPLOAD_HTTP_TIMEOUT): cv.All(
+                cv.positive_time_period_milliseconds,
+                cv.Range(max=TimePeriod(milliseconds=65535)),
+            ),
+            cv.Optional(
+                CONF_TFT_UPLOAD_WATCHDOG_TIMEOUT
+            ): cv.positive_time_period_milliseconds,
             cv.Optional(CONF_TFT_URL): cv.url,
             cv.Optional(CONF_TOUCH_SLEEP_TIMEOUT): cv.Any(
                 0, cv.int_range(min=3, max=65535)
@@ -123,7 +157,8 @@ CONFIG_SCHEMA = (
         }
     )
     .extend(cv.polling_component_schema("5s"))
-    .extend(uart.UART_DEVICE_SCHEMA)
+    .extend(uart.UART_DEVICE_SCHEMA),
+    _validate_tft_upload,
 )
 
 
@@ -176,6 +211,29 @@ async def to_code(config):
     if CONF_TFT_URL in config:
         cg.add_define("USE_NEXTION_TFT_UPLOAD")
         cg.add(var.set_tft_url(config[CONF_TFT_URL]))
+
+        # TFT upload HTTP timeout (default: 4.5s)
+        if CONF_TFT_UPLOAD_HTTP_TIMEOUT in config:
+            cg.add(
+                var.set_tft_upload_http_timeout(
+                    config[CONF_TFT_UPLOAD_HTTP_TIMEOUT].total_milliseconds
+                )
+            )
+
+        # TFT upload HTTP retries (default: 5)
+        if CONF_TFT_UPLOAD_HTTP_RETRIES in config:
+            cg.add(
+                var.set_tft_upload_http_retries(config[CONF_TFT_UPLOAD_HTTP_RETRIES])
+            )
+
+        # TFT upload watchdog timeout (default: 0 = no adjustment)
+        if CONF_TFT_UPLOAD_WATCHDOG_TIMEOUT in config:
+            cg.add(
+                var.set_tft_upload_watchdog_timeout(
+                    config[CONF_TFT_UPLOAD_WATCHDOG_TIMEOUT].total_milliseconds
+                )
+            )
+
         if CORE.is_esp32:
             # Re-enable ESP-IDF's HTTP client (excluded by default to save compile time)
             esp32.include_builtin_idf_component("esp_http_client")
diff --git a/esphome/components/nextion/nextion.cpp b/esphome/components/nextion/nextion.cpp
index c8c1b6fa412..cb20c34005c 100644
--- a/esphome/components/nextion/nextion.cpp
+++ b/esphome/components/nextion/nextion.cpp
@@ -191,6 +191,18 @@ void Nextion::dump_config() {
 #ifdef USE_NEXTION_MAX_QUEUE_SIZE
   ESP_LOGCONFIG(TAG, "  Max queue size: %zu", this->max_queue_size_);
 #endif
+#ifdef USE_NEXTION_TFT_UPLOAD
+  ESP_LOGCONFIG(TAG,
+                "  TFT URL: %s\n"
+                "  TFT upload HTTP timeout: %" PRIu16 "ms\n"
+                "  TFT upload HTTP retries: %u",
+                this->tft_url_.c_str(), this->tft_upload_http_timeout_, this->tft_upload_http_retries_);
+#ifdef USE_ESP32
+  if (this->tft_upload_watchdog_timeout_ > 0) {
+    ESP_LOGCONFIG(TAG, "  TFT upload WDT timeout: %" PRIu32 "ms", this->tft_upload_watchdog_timeout_);
+  }
+#endif  // USE_ESP32
+#endif  // USE_NEXTION_TFT_UPLOAD
 }
 
 void Nextion::update() {
diff --git a/esphome/components/nextion/nextion.h b/esphome/components/nextion/nextion.h
index c42ddba9b57..7999e3c4e3e 100644
--- a/esphome/components/nextion/nextion.h
+++ b/esphome/components/nextion/nextion.h
@@ -1071,6 +1071,33 @@ class Nextion : public NextionBase, public PollingComponent, public uart::UARTDe
   bool send_command_printf(const char *format, ...) __attribute__((format(printf, 2, 3)));
 
 #ifdef USE_NEXTION_TFT_UPLOAD
+  /**
+   * @brief Set the HTTP timeout for TFT upload requests.
+   * @param timeout_ms Timeout in milliseconds. Defaults to 4500ms (4.5s).
+   */
+  void set_tft_upload_http_timeout(uint16_t timeout_ms) { this->tft_upload_http_timeout_ = timeout_ms; }
+
+#ifdef USE_ESP32
+  /**
+   * @brief Set the watchdog timeout during TFT upload.
+   *
+   * The system watchdog timeout is temporarily adjusted to this value
+   * during the entire TFT transfer process and restored to the original
+   * value after the transfer completes (whether successful or not).
+   *
+   * A value of 0 means no watchdog adjustment (default).
+   *
+   * @param timeout_ms Watchdog timeout in milliseconds. 0 = no adjustment.
+   */
+  void set_tft_upload_watchdog_timeout(uint32_t timeout_ms) { this->tft_upload_watchdog_timeout_ = timeout_ms; }
+#endif  // USE_ESP32
+
+  /**
+   * @brief Set the number of HTTP retries for TFT upload requests.
+   * @param retries Number of retries. Defaults to 5. Range: 1-255.
+   */
+  void set_tft_upload_http_retries(uint8_t retries) { this->tft_upload_http_retries_ = retries; }
+
   /**
    * Set the tft file URL.
    */
@@ -1439,8 +1466,12 @@ class Nextion : public NextionBase, public PollingComponent, public uart::UARTDe
   int tft_size_ = 0;
   uint32_t original_baud_rate_ = 0;
   bool upload_first_chunk_sent_ = false;
+  uint16_t tft_upload_http_timeout_{4500};  ///< HTTP timeout in ms (default: 4.5s)
+  uint8_t tft_upload_http_retries_{5};      ///< HTTP retry count (default: 5)
 
 #ifdef USE_ESP32
+  uint32_t tft_upload_watchdog_timeout_{0};  ///< WDT timeout in ms (0 = no adjustment)
+
   /**
    * will request 4096 bytes chunks from the web server
    * and send each to Nextion
diff --git a/esphome/components/nextion/nextion_upload_arduino.cpp b/esphome/components/nextion/nextion_upload_arduino.cpp
index 46a04c1b2e1..e03f1f470b2 100644
--- a/esphome/components/nextion/nextion_upload_arduino.cpp
+++ b/esphome/components/nextion/nextion_upload_arduino.cpp
@@ -166,7 +166,7 @@ bool Nextion::upload_tft(uint32_t baud_rate, bool exit_reparse) {
   // Define the configuration for the HTTP client
   ESP_LOGV(TAG, "Init HTTP client, heap: %" PRIu32, EspClass::getFreeHeap());
   HTTPClient http_client;
-  http_client.setTimeout(15000);  // Yes 15 seconds.... Helps 8266s along
+  http_client.setTimeout(this->tft_upload_http_timeout_);
 
   bool begin_status = false;
 #ifdef USE_ESP8266
@@ -192,15 +192,15 @@ bool Nextion::upload_tft(uint32_t baud_rate, bool exit_reparse) {
   http_client.collectHeaders(header_names, 1);
   ESP_LOGD(TAG, "URL: %s", this->tft_url_.c_str());
   http_client.setReuse(true);
-  // try up to 5 times. DNS sometimes needs a second try or so
+
   int tries = 1;
   int code = http_client.GET();
   delay(100);  // NOLINT
 
   App.feed_wdt();
-  while (code != 200 && code != 206 && tries <= 5) {
-    ESP_LOGW(TAG, "HTTP fail: URL: %s; Error: %s, retry %d/5", this->tft_url_.c_str(),
-             HTTPClient::errorToString(code).c_str(), tries);
+  while (code != 200 && code != 206 && tries <= this->tft_upload_http_retries_) {
+    ESP_LOGW(TAG, "HTTP fail: URL: %s; Error: %s, retry %d/%u", this->tft_url_.c_str(),
+             HTTPClient::errorToString(code).c_str(), tries, this->tft_upload_http_retries_);
 
     delay(250);  // NOLINT
     App.feed_wdt();
diff --git a/esphome/components/nextion/nextion_upload_esp32.cpp b/esphome/components/nextion/nextion_upload_esp32.cpp
index 43f59a8d4b4..1014c728a81 100644
--- a/esphome/components/nextion/nextion_upload_esp32.cpp
+++ b/esphome/components/nextion/nextion_upload_esp32.cpp
@@ -7,6 +7,7 @@
 #include <esp_http_client.h>
 #include <cinttypes>
 #include "esphome/components/network/util.h"
+#include "esphome/components/watchdog/watchdog.h"
 #include "esphome/core/application.h"
 #include "esphome/core/defines.h"
 #include "esphome/core/helpers.h"
@@ -68,7 +69,7 @@ int Nextion::upload_by_chunks_(esp_http_client_handle_t http_client, uint32_t &r
     int partial_read_len = 0;
     uint8_t retries = 0;
     // Attempt to read the chunk with retries.
-    while (retries < 5 && read_len < buffer_size) {
+    while (retries < this->tft_upload_http_retries_ && read_len < buffer_size) {
       partial_read_len =
           esp_http_client_read(http_client, reinterpret_cast<char *>(buffer) + read_len, buffer_size - read_len);
       if (partial_read_len > 0) {
@@ -167,6 +168,9 @@ bool Nextion::upload_tft(uint32_t baud_rate, bool exit_reparse) {
     return false;
   }
 
+  // Temporarily adjust watchdog timeout for the duration of the TFT upload
+  watchdog::WatchdogManager wdm(this->tft_upload_watchdog_timeout_);
+
   this->connection_state_.is_updating_ = true;
 
   if (exit_reparse) {
@@ -190,7 +194,7 @@ bool Nextion::upload_tft(uint32_t baud_rate, bool exit_reparse) {
       .url = this->tft_url_.c_str(),
       .cert_pem = nullptr,
       .method = HTTP_METHOD_HEAD,
-      .timeout_ms = 15000,
+      .timeout_ms = static_cast<int>(this->tft_upload_http_timeout_),
       .disable_auto_redirect = false,
       .max_redirection_count = 10,
   };
diff --git a/esphome/components/select/select_call.h b/esphome/components/select/select_call.h
index c9abbc69a0b..fbe7b82e929 100644
--- a/esphome/components/select/select_call.h
+++ b/esphome/components/select/select_call.h
@@ -43,7 +43,7 @@ class SelectCall {
   Select *const parent_;
   optional<size_t> index_;
   SelectOperation operation_{SELECT_OP_NONE};
-  bool cycle_;
+  bool cycle_{false};
 };
 
 }  // namespace esphome::select
diff --git a/esphome/components/uponor_smatrix/uponor_smatrix.h b/esphome/components/uponor_smatrix/uponor_smatrix.h
index bd760f0d77d..bd20e9b6a0a 100644
--- a/esphome/components/uponor_smatrix/uponor_smatrix.h
+++ b/esphome/components/uponor_smatrix/uponor_smatrix.h
@@ -89,8 +89,8 @@ class UponorSmatrixComponent : public uart::UARTDevice, public Component {
 
   std::vector<uint8_t> rx_buffer_;
   std::queue<std::vector<uint8_t>> tx_queue_;
-  uint32_t last_rx_;
-  uint32_t last_tx_;
+  uint32_t last_rx_{0};
+  uint32_t last_tx_{0};
 
 #ifdef USE_TIME
   time::RealTimeClock *time_id_{nullptr};
diff --git a/esphome/components/wifi_info/wifi_info_text_sensor.h b/esphome/components/wifi_info/wifi_info_text_sensor.h
index 8ef35a5f5d1..7ade170c022 100644
--- a/esphome/components/wifi_info/wifi_info_text_sensor.h
+++ b/esphome/components/wifi_info/wifi_info_text_sensor.h
@@ -23,7 +23,7 @@ class IPAddressWiFiInfo final : public Component, public text_sensor::TextSensor
                    const network::IPAddress &dns2) override;
 
  protected:
-  std::array<text_sensor::TextSensor *, 5> ip_sensors_;
+  std::array<text_sensor::TextSensor *, 5> ip_sensors_{};
 };
 
 class DNSAddressWifiInfo final : public Component, public text_sensor::TextSensor, public wifi::WiFiIPStateListener {
diff --git a/esphome/components/x9c/x9c.h b/esphome/components/x9c/x9c.h
index 66c3df14e19..7dcd79bb7ce 100644
--- a/esphome/components/x9c/x9c.h
+++ b/esphome/components/x9c/x9c.h
@@ -25,9 +25,9 @@ class X9cOutput : public output::FloatOutput, public Component {
   InternalGPIOPin *cs_pin_;
   InternalGPIOPin *inc_pin_;
   InternalGPIOPin *ud_pin_;
-  float initial_value_;
-  float pot_value_;
-  int step_delay_;
+  float initial_value_{0.0f};
+  float pot_value_{0.0f};
+  int step_delay_{0};
 };
 
 }  // namespace x9c
diff --git a/esphome/core/application.h b/esphome/core/application.h
index 5baf0469b64..bde591e7c40 100644
--- a/esphome/core/application.h
+++ b/esphome/core/application.h
@@ -33,9 +33,6 @@
 #include <lwip/sockets.h>
 #endif
 #endif
-#if defined(USE_ESP8266) && defined(USE_SOCKET_IMPL_LWIP_TCP)
-#include "esphome/components/socket/socket.h"
-#endif
 #endif  // USE_SOCKET_SELECT_SUPPORT
 #if (defined(USE_ESP8266) || defined(USE_RP2040)) && defined(USE_SOCKET_IMPL_LWIP_TCP)
 namespace esphome::socket {
diff --git a/tests/components/nextion/common_tft_upload.yaml b/tests/components/nextion/common_tft_upload.yaml
new file mode 100644
index 00000000000..190abbc7b19
--- /dev/null
+++ b/tests/components/nextion/common_tft_upload.yaml
@@ -0,0 +1,5 @@
+display:
+  - id: !extend main_lcd
+    tft_url: http://esphome.io/default35.tft
+    tft_upload_http_timeout: 20s
+    tft_upload_http_retries: 10
diff --git a/tests/components/nextion/common_tft_upload_watchdog.yaml b/tests/components/nextion/common_tft_upload_watchdog.yaml
new file mode 100644
index 00000000000..385fee359e7
--- /dev/null
+++ b/tests/components/nextion/common_tft_upload_watchdog.yaml
@@ -0,0 +1,3 @@
+display:
+  - id: !extend main_lcd
+    tft_upload_watchdog_timeout: 30s
diff --git a/tests/components/nextion/test.esp32-ard.yaml b/tests/components/nextion/test.esp32-ard.yaml
index 7e94a9b4a5b..a4f71628dac 100644
--- a/tests/components/nextion/test.esp32-ard.yaml
+++ b/tests/components/nextion/test.esp32-ard.yaml
@@ -1,7 +1,5 @@
 packages:
   uart: !include ../../test_build_components/common/uart/esp32-ard.yaml
   base: !include common.yaml
-
-display:
-  - id: !extend main_lcd
-    tft_url: http://esphome.io/default35.tft
+  tft_upload: !include common_tft_upload.yaml
+  tft_upload_watchdog: !include common_tft_upload_watchdog.yaml
diff --git a/tests/components/nextion/test.esp32-idf.yaml b/tests/components/nextion/test.esp32-idf.yaml
index 99820f0f8da..259b71c9d04 100644
--- a/tests/components/nextion/test.esp32-idf.yaml
+++ b/tests/components/nextion/test.esp32-idf.yaml
@@ -1,7 +1,5 @@
 packages:
   uart: !include ../../test_build_components/common/uart/esp32-idf.yaml
   base: !include common.yaml
-
-display:
-  - id: !extend main_lcd
-    tft_url: http://esphome.io/default35.tft
+  tft_upload: !include common_tft_upload.yaml
+  tft_upload_watchdog: !include common_tft_upload_watchdog.yaml
diff --git a/tests/components/nextion/test.esp8266-ard.yaml b/tests/components/nextion/test.esp8266-ard.yaml
index 49f79b2f4c5..a2b0e727cce 100644
--- a/tests/components/nextion/test.esp8266-ard.yaml
+++ b/tests/components/nextion/test.esp8266-ard.yaml
@@ -1,7 +1,4 @@
 packages:
   uart: !include ../../test_build_components/common/uart/esp8266-ard.yaml
   base: !include common.yaml
-
-display:
-  - id: !extend main_lcd
-    tft_url: http://esphome.io/default35.tft
+  tft_upload: !include common_tft_upload.yaml