just saw this video https://www.youtube.com/watch?v=U-hVUczzlL4 and you get a very smart solution for a fair price, that does coordination etc.. and it's even esp32 based should the need arise. see https://www.bpcventilation.com/bsk-zephyr-single-room-heat-r...

I also have this DIY bookmarked: https://www.youtube.com/watch?v=wJB3dyHDa-8