I hate to rain on a cool personal project but you could just get a cheap z-wave dumb thermostat like a CT101 for $50 and hook it up to home assistant.
Solves the problem permanently, no risk of future deprecations.
Solves the problem permanently, no risk of future deprecations.
I just think that designing hardware to fit within another piece of dead hardware just to achieve what can be done off the shelf for $50 is not really my idea of a fun personal project.
Plenty of cheap thermostats have good aesthetics. The $30 round Honeywell analog thermostat is a timeless design. Their $30 non-programmable digital thermostat (RTH5160) is aesthetically pleasing enough, I certainly wouldn't call it ugly. I didn't interpret the stated goal of this project to be particularly relevant to aesthetics.