This will have been asked before, but I can't find it so sorry.
I have a Nest Learning Thermostat that is two floors away from my heat link in the basement. It just about stays connected, but I can't get it closer without removing it from the 'upstairs' zone.
If I bought a Nest Hub and put it halfway between the thermostat and the heat link, would that improve the connection? Would it act as a mesh point?
I do not have Google mesh WiFi.
In the case of a Nest thermostat/heat link, it appears my earlier comment was wrong,
We don't have a Nest thermostat or Heat Link, but a Google Mesh Wi-Fi would not help. When I tried looking it up in the installation guide, it seems the Nest thermostat and Nest Heat Link communicate wirelessly (up to 30 meters, supposedly) even if connected by cables, but they do NOT use your Wi-Fi router or network:
"The Heat Link doesn’t use your Wi-Fi router or network, instead, it uses a wireless mesh network called Thread to directly communicate with your thermostat."
And a Nest Hub (2nd Gen) can apparently function as a "Thread border router":
"Some of our products have radios for both networks and can act as Thread border routers."
So, it seems you COULD get a 2nd gen Nest Hub and place it midway between your Nest thermostat and your Nest Heat Link and it would function as a "Thread border router". I'm just another Google Nest customer, and don't know anything further. Maybe the above links will help you; the second link has instructions on creating a "Thread network".