I have ready as much as I can about this topic but still have not found the answer I am looking for.
I have a google home mini that has many devices connected such as Sonoff switches and Energenie TRV (Radiator) valve controllers. These work well with the Google Home but will not work with the Hubitat Home.
Question is can I set up a Hubitat to control everything that the Google Home sees?
Only way I'm aware of is to use Google Assistant Relay. This is a more advanced project, so if you're just starting out it might be a bit much to bite off.
It works by sending silent commands to Google Assistant via TTS messages. It doesn't give feedback whether or not the device has actually turned ON or OFF though. The only way I've found to do this is when a device type also supports IFTTT, I have had it flip a virtual switch linked back to Hubitat one way or the other to indicate status. That's a bit slow and requires additional rules. It works, but it's far from ideal.