Value from Scene not send to Zigbee thermostat

Hello,

I’m complete new to Home Assistant and struggle already on a small job.

Background:
In installed HA OS on a Pi4, installed the add-ons Mosquitto broker und Zigbee2MQTT.
Sucessfull paired with a Zigbee Thermostat.
I can controll it over the Dashboard, thats working fine.

Issue:
I created two scenes to adjust the temperature, one for the night and one for the day.
I tried it directly over HA and a second time over the Mosquitto broker add-on.
But when I excute the scenes the new target temperature is not set.
The Thermostat is shortly lightning up, but not changing the temperature.

What did I wrong?

Many Thanks from a Newbie

Thats how the scene look like in scenes.yaml:

<sub>- id: '1666947366821'
  name: Heizen2
  entities:
    climate.thermostat_arbeitszimmer:
      hvac_modes:
      - 'off'
      - auto
      - heat
      min_temp: 5
      max_temp: 30
      target_temp_step: 0.5
      current_temperature: 21.4
      temperature: 21
      friendly_name: Thermostat Arbeitszimmer
      supported_features: 1
      away_mode: 'OFF'
      battery: 35
      child_lock: UNLOCK
      color_mode: xy
      current_heating_setpoint: 21
      linkquality: 255
      local_temperature: 21.4
      preset: manual
      system_mode: heat
      valve_detection: 'ON'
      window_detection: 'ON'
      state: heat
  icon: mdi:home-thermometer
  metadata:
    climate.thermostat_arbeitszimmer:
      entity_only: true
- id: '1666949069015'
  name: Nachtabsenkung2
  entities:
    climate.thermostat_arbeitszimmer:
      hvac_modes:
      - 'off'
      - auto
      - heat
      min_temp: 5
      max_temp: 30
      target_temp_step: 0.5
      current_temperature: 21.4
      temperature: 17
      away_mode: 'OFF'
      battery: 35
      child_lock: UNLOCK
      color_mode: xy
      current_heating_setpoint: 17
      linkquality: 255
      local_temperature: 21.4
      position:
      preset: manual
      running_state:
      system_mode: heat
      valve_detection: 'ON'
      window_detection: 'ON'
      friendly_name: Thermostat Arbeitszimmer
      supported_features: 1
      state: heat
  icon: mdi:home-thermometer-outline
  metadata:
    climate.thermostat_arbeitszimmer:
      entity_only: true
</sub>

After wasting endless time on trying to figure out what’s the problem is, I gave up and used a blueprint from jheddings:
HVAC Daily Schedule Blueprint from jheddings