

Check the groups the working user is included in, and make sure the non-working user is in those same groups. See if anything there.
Edit: Oh, you know what. I think this is probably Pipewire not starting for multiple users when multiple are logged in. On the non-working user, you need to start a unique Pipewire session for that user, because the other working user’s session can’t be shared by default.
Yeah, see my edit. This is a Pipewire session thing. Each user needs a unique Pipewire session to do audio. Video has nothing to do with Pipewire.