Show Power/Energy sent from Watwächter via MQTT to HA in the Energy Dashboard

Energy
1

My Wattwächter (https://www.smartcircuits.de/) sends values of the electricity meter via MQTT to HA.

The entities are not listed in the dashboard.
So far I read and tried to understand the following articles:

But I did not get it running.
My configuration.yaml is

# Loads default set of integrations. Do not remove.
default_config:

# Load frontend themes from the themes folder
frontend:
  themes: !include_dir_merge_named themes

automation: !include automations.yaml
script: !include scripts.yaml
scene: !include scenes.yaml

# Added block for Energy Dashboard
# see https://community.home-assistant.io/t/add-a-mqtt-entity-to-energy-dashboard/502878/8

Template:
  - sensor:
      - name: "Energy kWh"
        unique_id: "sensor.p6_pv_lk13be_power_total_out_2"
        unit_of_measurement: "kWh"
        device_class: energy
        state_class: total_increasing
        state: "{{ states('sensor.p6_pv_lk13be_power_total_out_2')|float(0) }}"
        availability: "{{ states('sensor.p6_pv_lk13be_power_total_out_2')|is_number }}"

I wonder if it is correct to configure something about a “leaf” in a global file. I am very new to HA, but I had expected that there is a yaml file per device or per entity.

Developer tools / statistics prints No issue and it can plot the data.

Any ideas, what I could be missing?