I have a vey similar problem.
It’s happening in my iPad PRO M1, and MBP M1.. when i restart the devices i am able to stream via Airplay2. But after a undetermined amount of time not playing music, the problem appears.
BUT
In my iPhone 12 PRO works perfectly!!
I’ve tried some workarounds B&O support suggested to do, deleting my Beosound2 from my account and setup again.. but nothing helped.
I’ve noticed, in January 12, 2022 B&O updated BS2 firmware. I came back from holidays some days after with this new problem. Maybe this has something to do.
i am waiting further instructions from B&O support. Will see..