That's what I do at home. I have little Xiaomi LYWSD002MMC and LYWSD003MMC devices (the latter with custom firmware - pvvx) and my radiators are switched on or off (via their pilot wire) by an ESP device, using a few rules to lower the temperature when nobody's there. It works much better than the radiator's own thermostat.

I control my devices (I have a lot more than just for the radiators) through a kind of interface that I wrote myself (PHP and only very few, reliable dependencies) because I hate maintaining Home Assistant.