Request for Generic Thermostat "heater" switch to act as a thermostat physical switch

How does this work for you? Seems to me that’s what user panhans uses in:

To detect a TRV’s physical change, these lines does the job (5 seconds and context conditions):

# trigger
  - platform: state
    entity_id: !input input_trvs
    attribute: temperature
    for:
      seconds: 5
    id: comfort_change

# further condition
      - condition: template
        value_template: "{{ trigger.id == 'comfort_change' and input_temperature_comfort != none and trigger.to_state.context.id != none and trigger.to_state.context.parent_id == none and trigger.to_state.context.user_id == none }}"