I have a CT101 RADIOTHERMOSTAT. O tried multiple times to add to Google Assistant to be able to control via voice, but it doesn't show up in Assistant. I have tried relinking repairing and everything else. Your notes say it is compatible
The Radio Thermostat (CT101) is compatible and works with Google Assistant; what you are seeing is not expected behavior - sorry about that. If you don't mind DM'ing me your Iris hub ID we can look into this further.