Set current_temperature attribute of my Climates (Automation)

Hello.
I am using some Devolo Radial Thermostats. They are connected with the Devolo Home Control Integration to my Home Assistant.
But it does not read the temperature sensor for getting the current temperautre.
The current_temperature attribute is always 0.
I am using some Xiaomi Aqara Temperature Sensors in each room. But the Sensor Values are not usable with Google Home.
My best solution to get the current Temperature with a voice command has to set the current_temperature attribute of each thermostat.
It works great if I manually use the Dev-Tools. But how to automate this? I can not find any service which allows me to change any attribute of a entity.
A general Service like: attribute_set_value which allows to select the target entity and the attribute and offers a value parameter would be great.

I am not sure if I missed something, so I decided to not mark this as Feature-Request at first.

Thanks.

found a solution