I see various threads about this integration, but they all seem to be quite old.
(i am currently using the Honeywell Advanced Thermostat driver, but same result with the built in one)
I can view my thermostat in Google Home, and Google Assistant provides me an option to change the temperature.
When I change the temp via google, nothing actually happens.
I am coming from smartthings/nest thermostat that was consistent, so this transition has been a bit rough for me as far as thermostats go.
I have this same setup and everything was working great for over a year. A few days ago the Google Home AND Hubitat apps lost control of the Honeywell T6. I changed to the advanced driver and that fixed the hubitat app but not Google. I redid everything on the Google side but no luck. When I use voice commands now Google says it's changing the temp and nothing happens. Everything else seems to work (cool to heat mode) just not the temp.