Trying to make a puck js doorbell and need advice on range

The best reference is https://www.espruino.com/Reference - and there's a specific one for Puck.js which shows you only the stuff that's available: https://www.espruino.com/ReferencePUCKJS

I tried out using BTHome on my Bangle JS and it was picked up in the 2nd floor bedroom through two different floors

That's great! Also those thermometers look neat - I might have to give those a try!