When playing games on my iPhone 12 Pro Max there is a issue with the sound. It increase from low to high during play. I don't know if this is a hardware or software releated problem? I using iOS 14.4 beta 2. I also have this issue in 14.3.
I’ve actually been having the opposite issue. I’ll have my ringer and volume maxed out then, without fail, all the way down to nothing, or barely nothing. The back of my phone near the Apple logo gets hot when this starts happening too