Bluetooth is Bluetooth, you can connect any Bluetooth audio to the PlayStation. But... You might not be able to use voice or other enhancements. Sony will tell you you can only use Sony headphones with the PS5 but there is no technical reason for that.
I think multipoint audio means you can seamlessly switch, not necessarily use it with multiple sources simultaneously. More info from Soundguys saying the same You could just play music on the Steam Deck though.
ANC takes sound from the environment with microphones and plays cancelling waves. In combination with closed back cans you should not hear anything from your surroundings. That said, it's not perfect tech. Make sure to read a couple reviews (you can use the Soundguys website) to see what pro's think.