Copy a number from one entity to another

Here I am again asking for help. The project that controls my heating is growing and with it the difficulties too.
Now I find myself hitting my brain on this problem:
I wanted to make the thermostat work with the outside temperature which provides me with weather integration


but it doesn’t recognize this as “target_ sensor”. So I created an entity called “input_number.meteo_temperature” and tried to copy the temperature value into it.
I am trying to create the model to do this but I run into constant errors. Very frustrating.
I still hope for your help to get out.

Use a template sensor

- sensor:
  - name: "Outside temperature"
    device_class: "temperature"
    state: >
      {{ state_attr("", "temperature") }}

My goodness! it was that simple. Now it works the way I wanted. I have to reread the tutorials more carefully.
Thank you