This is the way. Though this isn't exactly cheap to start, I have a $50 eBay thin client (including the price of throwing an ssd in there), a $30 sonoff zigbee controller, install Home Assistant, and boom you're off to the races. Ikea's stuff (as well as Phillips hue, which I was able to snag some deals on clearance for) and Lutron Caseta are all zigbee so I have complete local control over most things in my house, minus a few wifi pieces that I've been replacing over time. We do similar with the 5 button remotes, and I also have a few different button controllers from sonoff. Ikea's motion sensors have also been rock solid for me.

And yeah, heating is currently my white whale. My home has electric radiant heating which leaves my only option for thermostats down to one or two units that are $120 or so, and I have like 7-8 in total in the home so that's just going to have to stay manual for now. Space heater isn't a bad idea, though.