I'm looking to replace a "dumb" thermostat in my house. My biggest problem is, the Family (well MIL) will be the primary user of said thermostat. Were it up to me, i'd just duplicate the setup I have in my detached garage (ESP32 and 4channel relay board, with remote temp sensors).
My second biggest problem is many of the smart thermostats requiring internet access and control only being available through their External API. Ideally I'd like something that is 100% local control, with opt in for any remote data.

What setups do you have? do you like it? is it "normal" person friendly?