Using input_text for sunrise offset

I’m trying to build a component from the UI that will allow me to input a sunrise offset value in an automation.

My input_text is defined as:

morning_light_offset:
  name: Sunrise Offset
  icon: mdi:timer
  initial: '00:15:00'
  pattern: '^[+-]\d{2}:\d{2}:\d{2}$

And my automation is configure as such:

  - alias: 'Turn off Living Room lights after sunrise'
    initial_state: true
    trigger:
      - platform: sun
        event: sunrise
        offset: template
        value_template: "{{ states.input_text.morning_light_offset.state }}"
    action:
      - service: light.turn_off
        entity_id: light.lr1_3, light.lr2_34

I’ve also tried using just offset: "{{ states.input_text.morning_light_offset.state }}" as well as a number of other attempts. But regardless of what I try I get the same error when I validate the configuration:

Invalid config for [automation]: extra keys not allowed @ data['trigger'][0]['value_template']. Got None
offset template should be format 'HH:MM' or 'HH:MM:SS' for dictionary value @ data['trigger'][0]['offset']. Got None. (See /home/homeassistant/.homeassistant/configuration.yaml, line 70). Please check the docs at https://home-assistant.io/components/automation/

As far as I know, the sun component doesn’t support templates for offset.

Well that’s not what I wanted to hear, but that also could be why I couldn’t get it to work nor could I find anything similar on the forums.

Anyone care to confirm (or preferably deny) that this won’t work?