diff --git a/esphome/components/ble_client/automation.h b/esphome/components/ble_client/automation.h
index 46915be9ed..9c5646b3d1 100644
--- a/esphome/components/ble_client/automation.h
+++ b/esphome/components/ble_client/automation.h
@@ -107,15 +107,14 @@ template<typename... Ts> class BLEClientWriteAction : public Action<Ts...>, publ
   void set_char_uuid128(uint8_t *uuid) { this->char_uuid_ = espbt::ESPBTUUID::from_raw(uuid); }
 
   void set_value_template(std::vector<uint8_t> (*func)(Ts...)) {
-    this->value_.template_func = func;
-    this->has_simple_value_ = false;
+    this->value_.func = func;
+    this->len_ = -1;  // Sentinel value indicates template mode
   }
 
   // Store pointer to static data in flash (no RAM copy)
   void set_value_simple(const uint8_t *data, size_t len) {
-    this->value_.simple_data.ptr = data;
-    this->value_.simple_data.len = len;
-    this->has_simple_value_ = true;
+    this->value_.data = data;
+    this->len_ = len;  // Length >= 0 indicates static mode
   }
 
   void play(const Ts &...x) override {}
@@ -124,10 +123,12 @@ template<typename... Ts> class BLEClientWriteAction : public Action<Ts...>, publ
     this->num_running_++;
     this->var_ = std::make_tuple(x...);
     std::vector<uint8_t> value;
-    if (this->has_simple_value_) {
-      value.assign(this->value_.simple_data.ptr, this->value_.simple_data.ptr + this->value_.simple_data.len);
+    if (this->len_ >= 0) {
+      // Static mode: copy from flash to vector
+      value.assign(this->value_.data, this->value_.data + this->len_);
     } else {
-      value = this->value_.template_func(x...);
+      // Template mode: call function
+      value = this->value_.func(x...);
     }
     // on write failure, continue the automation chain rather than stopping so that e.g. disconnect can work.
     if (!write(value))
@@ -202,13 +203,10 @@ template<typename... Ts> class BLEClientWriteAction : public Action<Ts...>, publ
 
  private:
   BLEClient *ble_client_;
-  bool has_simple_value_{true};
+  ssize_t len_{-1};  // -1 = template mode, >=0 = static mode with length
   union Value {
-    std::vector<uint8_t> (*template_func)(Ts...);
-    struct {
-      const uint8_t *ptr;
-      size_t len;
-    } simple_data;
+    std::vector<uint8_t> (*func)(Ts...);  // Function pointer (stateless lambdas)
+    const uint8_t *data;                  // Pointer to static data in flash
   } value_;
   espbt::ESPBTUUID service_uuid_;
   espbt::ESPBTUUID char_uuid_;
diff --git a/esphome/components/canbus/canbus.h b/esphome/components/canbus/canbus.h
index 122ccfe39e..f7b84111bd 100644
--- a/esphome/components/canbus/canbus.h
+++ b/esphome/components/canbus/canbus.h
@@ -115,14 +115,13 @@ template<typename... Ts> class CanbusSendAction : public Action<Ts...>, public P
   void set_data_template(std::vector<uint8_t> (*func)(Ts...)) {
     // Stateless lambdas (generated by ESPHome) implicitly convert to function pointers
     this->data_.func = func;
-    this->static_ = false;
+    this->len_ = -1;  // Sentinel value indicates template mode
   }
 
   // Store pointer to static data in flash (no RAM copy)
   void set_data_static(const uint8_t *data, size_t len) {
-    this->data_.static_data.ptr = data;
-    this->data_.static_data.len = len;
-    this->static_ = true;
+    this->data_.data = data;
+    this->len_ = len;  // Length >= 0 indicates static mode
   }
 
   void set_can_id(uint32_t can_id) { this->can_id_ = can_id; }
@@ -138,9 +137,11 @@ template<typename... Ts> class CanbusSendAction : public Action<Ts...>, public P
     auto use_extended_id =
         this->use_extended_id_.has_value() ? *this->use_extended_id_ : this->parent_->use_extended_id_;
     std::vector<uint8_t> data;
-    if (this->static_) {
-      data.assign(this->data_.static_data.ptr, this->data_.static_data.ptr + this->data_.static_data.len);
+    if (this->len_ >= 0) {
+      // Static mode: copy from flash to vector
+      data.assign(this->data_.data, this->data_.data + this->len_);
     } else {
+      // Template mode: call function
       data = this->data_.func(x...);
     }
     this->parent_->send_data(can_id, use_extended_id, this->remote_transmission_request_, data);
@@ -150,14 +151,11 @@ template<typename... Ts> class CanbusSendAction : public Action<Ts...>, public P
   optional<uint32_t> can_id_{};
   optional<bool> use_extended_id_{};
   bool remote_transmission_request_{false};
-  bool static_{true};  // Default to static mode (most common case)
+  ssize_t len_{-1};  // -1 = template mode, >=0 = static mode with length
   union Data {
-    std::vector<uint8_t> (*func)(Ts...);  // 4 bytes on 32-bit
-    struct {
-      const uint8_t *ptr;  // 4 bytes on 32-bit
-      size_t len;          // 4 bytes on 32-bit
-    } static_data;         // 8 bytes total on 32-bit
-  } data_;                 // Union size = 8 bytes (max of 4 and 8)
+    std::vector<uint8_t> (*func)(Ts...);  // Function pointer (stateless lambdas)
+    const uint8_t *data;                  // Pointer to static data in flash
+  } data_;
 };
 
 class CanbusTrigger : public Trigger<std::vector<uint8_t>, uint32_t, bool>, public Component {
diff --git a/esphome/components/remote_base/raw_protocol.h b/esphome/components/remote_base/raw_protocol.h
index 9b671e611f..941b6aab42 100644
--- a/esphome/components/remote_base/raw_protocol.h
+++ b/esphome/components/remote_base/raw_protocol.h
@@ -42,17 +42,20 @@ class RawTrigger : public Trigger<RawTimings>, public Component, public RemoteRe
 
 template<typename... Ts> class RawAction : public RemoteTransmitterActionBase<Ts...> {
  public:
-  void set_code_template(std::function<RawTimings(Ts...)> func) { this->code_func_ = func; }
+  void set_code_template(RawTimings (*func)(Ts...)) {
+    this->code_.func = func;
+    this->len_ = -1;  // Sentinel value indicates template mode
+  }
   void set_code_static(const int32_t *code, size_t len) {
-    this->code_static_ = code;
-    this->code_static_len_ = len;
+    this->code_.data = code;
+    this->len_ = len;  // Length >= 0 indicates static mode
   }
   TEMPLATABLE_VALUE(uint32_t, carrier_frequency);
 
   void encode(RemoteTransmitData *dst, Ts... x) override {
-    if (this->code_static_ != nullptr) {
-      for (size_t i = 0; i < this->code_static_len_; i++) {
-        auto val = this->code_static_[i];
+    if (this->len_ >= 0) {
+      for (size_t i = 0; i < static_cast<size_t>(this->len_); i++) {
+        auto val = this->code_.data[i];
         if (val < 0) {
           dst->space(static_cast<uint32_t>(-val));
         } else {
@@ -60,15 +63,17 @@ template<typename... Ts> class RawAction : public RemoteTransmitterActionBase<Ts
         }
       }
     } else {
-      dst->set_data(this->code_func_(x...));
+      dst->set_data(this->code_.func(x...));
     }
     dst->set_carrier_frequency(this->carrier_frequency_.value(x...));
   }
 
  protected:
-  std::function<RawTimings(Ts...)> code_func_{nullptr};
-  const int32_t *code_static_{nullptr};
-  int32_t code_static_len_{0};
+  ssize_t len_{-1};  // -1 = template mode, >=0 = static mode with length
+  union Code {
+    RawTimings (*func)(Ts...);
+    const int32_t *data;
+  } code_;
 };
 
 class RawDumper : public RemoteReceiverDumperBase {
diff --git a/esphome/components/sx126x/automation.h b/esphome/components/sx126x/automation.h
index 41f0a888e5..2282c583cb 100644
--- a/esphome/components/sx126x/automation.h
+++ b/esphome/components/sx126x/automation.h
@@ -16,33 +16,31 @@ template<typename... Ts> class SendPacketAction : public Action<Ts...>, public P
  public:
   void set_data_template(std::vector<uint8_t> (*func)(Ts...)) {
     this->data_.func = func;
-    this->static_ = false;
+    this->len_ = -1;  // Sentinel value indicates template mode
   }
 
   void set_data_static(const uint8_t *data, size_t len) {
-    this->data_.static_data.ptr = data;
-    this->data_.static_data.len = len;
-    this->static_ = true;
+    this->data_.data = data;
+    this->len_ = len;  // Length >= 0 indicates static mode
   }
 
   void play(const Ts &...x) override {
     std::vector<uint8_t> data;
-    if (this->static_) {
-      data.assign(this->data_.static_data.ptr, this->data_.static_data.ptr + this->data_.static_data.len);
+    if (this->len_ >= 0) {
+      // Static mode: copy from flash to vector
+      data.assign(this->data_.data, this->data_.data + this->len_);
     } else {
+      // Template mode: call function
       data = this->data_.func(x...);
     }
     this->parent_->transmit_packet(data);
   }
 
  protected:
-  bool static_{true};
+  ssize_t len_{-1};  // -1 = template mode, >=0 = static mode with length
   union Data {
-    std::vector<uint8_t> (*func)(Ts...);
-    struct {
-      const uint8_t *ptr;
-      size_t len;
-    } static_data;
+    std::vector<uint8_t> (*func)(Ts...);  // Function pointer (stateless lambdas)
+    const uint8_t *data;                  // Pointer to static data in flash
   } data_;
 };
 
diff --git a/esphome/components/sx127x/automation.h b/esphome/components/sx127x/automation.h
index 52dbf37e09..fb0367fcca 100644
--- a/esphome/components/sx127x/automation.h
+++ b/esphome/components/sx127x/automation.h
@@ -16,33 +16,31 @@ template<typename... Ts> class SendPacketAction : public Action<Ts...>, public P
  public:
   void set_data_template(std::vector<uint8_t> (*func)(Ts...)) {
     this->data_.func = func;
-    this->static_ = false;
+    this->len_ = -1;  // Sentinel value indicates template mode
   }
 
   void set_data_static(const uint8_t *data, size_t len) {
-    this->data_.static_data.ptr = data;
-    this->data_.static_data.len = len;
-    this->static_ = true;
+    this->data_.data = data;
+    this->len_ = len;  // Length >= 0 indicates static mode
   }
 
   void play(const Ts &...x) override {
     std::vector<uint8_t> data;
-    if (this->static_) {
-      data.assign(this->data_.static_data.ptr, this->data_.static_data.ptr + this->data_.static_data.len);
+    if (this->len_ >= 0) {
+      // Static mode: copy from flash to vector
+      data.assign(this->data_.data, this->data_.data + this->len_);
     } else {
+      // Template mode: call function
       data = this->data_.func(x...);
     }
     this->parent_->transmit_packet(data);
   }
 
  protected:
-  bool static_{true};
+  ssize_t len_{-1};  // -1 = template mode, >=0 = static mode with length
   union Data {
-    std::vector<uint8_t> (*func)(Ts...);
-    struct {
-      const uint8_t *ptr;
-      size_t len;
-    } static_data;
+    std::vector<uint8_t> (*func)(Ts...);  // Function pointer (stateless lambdas)
+    const uint8_t *data;                  // Pointer to static data in flash
   } data_;
 };
 
diff --git a/esphome/components/uart/automation.h b/esphome/components/uart/automation.h
index 7a3344c2f1..c2eb308eb8 100644
--- a/esphome/components/uart/automation.h
+++ b/esphome/components/uart/automation.h
@@ -12,36 +12,33 @@ template<typename... Ts> class UARTWriteAction : public Action<Ts...>, public Pa
  public:
   void set_data_template(std::vector<uint8_t> (*func)(Ts...)) {
     // Stateless lambdas (generated by ESPHome) implicitly convert to function pointers
-    this->data_.func = func;
-    this->static_ = false;
+    this->code_.func = func;
+    this->len_ = -1;  // Sentinel value indicates template mode
   }
 
   // Store pointer to static data in flash (no RAM copy)
   void set_data_static(const uint8_t *data, size_t len) {
-    // Simply set pointer and length - no construction needed for POD types
-    this->data_.static_data.ptr = data;
-    this->data_.static_data.len = len;
-    this->static_ = true;
+    this->code_.data = data;
+    this->len_ = len;  // Length >= 0 indicates static mode
   }
 
   void play(const Ts &...x) override {
-    if (this->static_) {
-      this->parent_->write_array(this->data_.static_data.ptr, this->data_.static_data.len);
+    if (this->len_ >= 0) {
+      // Static mode: use pointer and length
+      this->parent_->write_array(this->code_.data, static_cast<size_t>(this->len_));
     } else {
-      auto val = this->data_.func(x...);
+      // Template mode: call function
+      auto val = this->code_.func(x...);
       this->parent_->write_array(val);
     }
   }
 
  protected:
-  bool static_{true};  // Default to static mode (most common case)
-  union Data {
+  ssize_t len_{-1};  // -1 = template mode, >=0 = static mode with length
+  union Code {
     std::vector<uint8_t> (*func)(Ts...);  // Function pointer (stateless lambdas)
-    struct {
-      const uint8_t *ptr;
-      size_t len;
-    } static_data;
-  } data_;
+    const uint8_t *data;                  // Pointer to static data in flash
+  } code_;
 };
 
 }  // namespace uart
diff --git a/esphome/components/udp/automation.h b/esphome/components/udp/automation.h
index a3b76fb4ea..b66c2a9892 100644
--- a/esphome/components/udp/automation.h
+++ b/esphome/components/udp/automation.h
@@ -13,32 +13,30 @@ template<typename... Ts> class UDPWriteAction : public Action<Ts...>, public Par
  public:
   void set_data_template(std::vector<uint8_t> (*func)(Ts...)) {
     this->data_.func = func;
-    this->static_ = false;
+    this->len_ = -1;  // Sentinel value indicates template mode
   }
 
   void set_data_static(const uint8_t *data, size_t len) {
-    this->data_.static_data.ptr = data;
-    this->data_.static_data.len = len;
-    this->static_ = true;
+    this->data_.data = data;
+    this->len_ = len;  // Length >= 0 indicates static mode
   }
 
   void play(const Ts &...x) override {
-    if (this->static_) {
-      this->parent_->send_packet(this->data_.static_data.ptr, this->data_.static_data.len);
+    if (this->len_ >= 0) {
+      // Static mode: pass pointer directly to send_packet(const uint8_t *, size_t)
+      this->parent_->send_packet(this->data_.data, static_cast<size_t>(this->len_));
     } else {
+      // Template mode: call function and pass vector to send_packet(const std::vector<uint8_t> &)
       auto val = this->data_.func(x...);
       this->parent_->send_packet(val);
     }
   }
 
  protected:
-  bool static_{true};
+  ssize_t len_{-1};  // -1 = template mode, >=0 = static mode with length
   union Data {
-    std::vector<uint8_t> (*func)(Ts...);
-    struct {
-      const uint8_t *ptr;
-      size_t len;
-    } static_data;
+    std::vector<uint8_t> (*func)(Ts...);  // Function pointer (stateless lambdas)
+    const uint8_t *data;                  // Pointer to static data in flash
   } data_;
 };
 
diff --git a/tests/components/remote_transmitter/common-buttons.yaml b/tests/components/remote_transmitter/common-buttons.yaml
index 101d60a893..d48d36bd54 100644
--- a/tests/components/remote_transmitter/common-buttons.yaml
+++ b/tests/components/remote_transmitter/common-buttons.yaml
@@ -136,10 +136,16 @@ button:
         address: 0x00
         command: 0x0B
   - platform: template
-    name: RC5 Raw
+    name: RC5 Raw static
     on_press:
       remote_transmitter.transmit_raw:
         code: [1000, -1000]
+  - platform: template
+    name: RC5 Raw lambda
+    on_press:
+      remote_transmitter.transmit_raw:
+        code: !lambda |-
+          return {(int32_t)id(test_number).state * 100, -1000};
   - platform: template
     name: AEHA
     id: eaha_hitachi_climate_power_on