Google Nest integration

Well, i went into a huge rabbit hole and I have no clue how to do this:

I have a Google Nest thermostat and a couple of temperature sensors scattered around the house. Since I cant do a “zone” system, I have to turn off the Google Nest whenever it gets too hot/cold in one of the other rooms. I thought I could do that by sending a notification to the Google Home whenever the temperature went too high on one of the sensors.

However, Google Home does not detect my temperature sensors, and I can’t seem to send messages to my Google Home to control the temperature. Which makes the whole “Works with Google Home” look like a marketing thing than it actually does what it was promised.

I know there is something called “Google Home Automatisation” and it shows some promising ideas with APIs, however I am unable to send temperature messages to my Nest because I need some oAuth lingo. Can anyone here tell me how to send temperature notifications to the Nest using LUUP, because my wife is literally scolding me for buying a lot of automatisation stuff for something that cannot be automated…