I use Google Nest Mini's, never got to automate the home, we got them as VHF radio does not work where we live, so we get same radio stations from internet with the Nest Mini, and two can be paired to give stereo.
It used Google Home app on the phone, but in the main just voice commands, we decided not to put central heating to be controlled by google, but it has somehow connected to it anyway, so Hey google set living room to 22°C and the two TRV heads and wall thermostat all change to 22°C. As long as items say works with Google Home, it can control them.
But in the early days, it could behave like a young child, it would turn off lights, and we would ask it to turn them back on, and it would say it has not been programmed to do that yet, but it turned them off!
So each new light bulb we get, first we have to pair it with the special bulbs program, then connect to google home in my case. So with Smart Life for example
I select Third party Voice Service, then

and then

showing in my case already linked, in my case

is the option selected. I have tried to use IFTTT, to control my socket's old Energenie ones, as it gave 3 slots, and I wanted 4 slots, it did work, but not that easy to set up. Did look at geo-fencing, tried with Google Nest Gen 3, it was hopeless, would switch off, when we left, OK, but on return nearly home before it would turn back on, I note that Drayton Wiser uses IFTTT, but never tried to set it up. Would be interesting to hear how anyone else set it up. Basic oil boiler is OK keeping the house warm, but to reheat from cold, a bit slow, I cheat in the morning, and turn up the TRV heads in sequence, so major rooms heated first.
But hey google turn on Christmas has just turned on all my Christmas lights, and it uses so little power, not worried if it turns on at wrong time. Main point is on leaving the room, hey google turn off living room, turns off multi-power plugs, and main lights all with one command, no need to walk around them all.
Good luck, tell me how it goes.