I want the UI of an old Honeywell mercury switch thermostat. Heat/Cool mode switch and dial to set the desired temperature. That’s it. Absolutely simple to understand and operate.
The last apartment I lived in installed new "smart" thermostats throughout the building. It always seemed to change the target temperature at random and I got so frustrated that I swapped it out with a dumb Honeywell one (and swapped it back when I moved out). I never found having to make the occasional manual adjustment to be an issue.