Welcome to the world of electronic gadgets. You’re right there’s nowhere near $100 worth of hardware in this thing. I’d also love a color touchscreen. But I’d rather a color touchscreen that I could integrate in HA than one running some proprietary cloud connected ThermostatOS.

You could do that yourself- put an old tablet on the wall, run power to it, then get something like a zooz zen16 multi-relay or an ESPHome relay board to drive the hvac. Then the thermostat becomes a totally software defined virtual thing in Home Assistant that pulls data from a temp sensor in the room and controls the HVAC as appropriate.