I'm thinking it should be possible but I can't figure out how: Can you simultaneously play music on a Bluetooth speaker and record video at the same time with the same phone?
Every thing I try pauses the audio I'm trying to play when I hit record in the camera app.
I have tried the 'start music, start recording, pause recording, start music from tray, resume recording' sequence and the music refused to resume.
I played music on Spotify from phone speakers (no bluetooth) and started recording. Music stopped, I opened the tray and hit the play button, music continued playing. I am assuming this was made as a QoL feature but didn't implement it well instead of a device or software limitation. Galaxy A34, Android 13 latest update, in a region where carrier doesn't matter :)
EDIT: It takes a few taps on the play button to start playing.
Maybe you can restrict permissions of camera app via adb, the app has a permission called "change audio settings". Or simply use another camera app.