Input_slider initial value

Configuration
1

How can I get this working? I would like to set the initial value based on a sensor state.

customize:
    automation.ThermostatSliderSet:
      hidden: true      
    automation.SetThermostatvalue:
      hidden: true

input_slider:
  thermo_temp:
    name: "Thermostat Temperature"
    min: 5
    max: 30
    step: 0.1
    unit_of_measurement: step
  
automation:
  - alias: 'ThermostatSliderSet'
    trigger:
      platform: state
      entity_id: input_slider.thermo_temp
    action:
      service: "mqtt.publish"
      data_template:
        topic: "nefit/temp/set"
        retain: "false"
        payload: '{{states("input_slider.thermo_temp")}}'
        
  - alias: 'SetThermostatvalue'
    trigger:
      platform: state
      entity_id: input_slider.setpoint_room_temperature
    action:
      service: input_slider.select_value
      data_template:
        entity_id: input_slider.thermo_temp
        value: '{{states("input_slider.setpoint_room_temperature")}}'

sensor:
  - platform: rest
    resource: http://127.0.0.1:3000/bridge/heatingCircuits/hc1/temperatureRoomManual
    value_template: '{{ value_json.value }}'
    method: GET
    name: "Setpoint Room Temperature"
    unit_of_measurement: "°C"
2

Any solution to this problem? I have the same ned for a volume slider.

Thanks