Now, about the wifi part, why isn't there an Home Assistant extension that detects already room presence magically exploiting all of this??
There is: https://community.home-assistant.io/t/espectre-wi-fi-motion-...
There is with Zigbee: https://github.com/orgs/home-assistant/discussions/960
There is: https://community.home-assistant.io/t/espectre-wi-fi-motion-...