I tried Room Assistant a year or 2 ago and it SUCKED. I have a 4 storey townhouse and had 2 nodes running Room Assistant and I could be stood next to 1, two floors away from the other and that's the one it said I was closest to.
The idea is that by detecting the strength of the Bluetooth signal, the node with the best signal was closest, but it just didn't work (for me).
Anyway espresence is better, especially because I've doubled up and I bought 4 esp32 boards with pins off AliExpress for under £12, and arrived within a week.
You connect the little chip to your pc and flash a firmware from Google Chrome, then hook it into your WiFi, go to its page and give it a name, and hook it into your MQTT.
4 boards later I have a node per floor.
Next I added our phones to it by pairing them to it, then deleting the pairing on the phone. Add the Bluetooth connection to HA config and you're away! Well...
So you have to connect what the boards say to what it means in HA yourself. You get "bedroom" off Espresence and have a Bedroom zone but you have to put the pieces together yourself.
I ended up making binary sensors for each room in Node Red. Did I leave the room? Who else is there, nobody? Ok mark it clear... You could just make helper switches and use them but I was feeling fancy. I've already posted recently about the Binary sensor.
But once you've done that, you just base your automations off the state of the switches you made.
So the age old "The front room motion sensor stopped detecting, should the lights go off?" question, now becomes...
Huh I must have stopped typing there...
...much easier to solve. I can still have the old "TV on?, wife's laptop connected to Bluetooth?" bits in, but having Bluetooth presence detection AS WELL makes it much more reliable, for a measly £12