iPhone volume turns down when I switch apps/screen goes to sleep…

The volume on my phone lowers when I open certain apps or unlock my phone… and not just lowers, but it’s like the speakers themselves get quieter, so I can’t even make it louder if I try to turn the volume up because sometimes it’s already at max volume. Every now and then the reverse will happen, where suddenly the speakers will just blast… but the overall volume of the phone going down happens more often.

It happens a lot when I turn on my screen after it's been dark, but also happens randomly when I open other apps, including iMessage, Gmail, and Firefox… many apps that aren’t currently producing sounds.

I've turned off "Attention Aware" and "Reduce Loud Sounds", and I’ve adjusted in-app settings in Spotify (since it happens in there more often and disrupts my listening experience)… and I am definitely NOT pressing the volume buttons by accident. Sometimes I can't even turn it back up manually because the phone is already set to max volume, but it gets so quiet I can barely hear it.

This problem is through the phone speakers, as well as via Bluetooth connections.

Super annoying issue!!!! And so far I see no solution posted. I shouldn’t have to close and restart an up-to-date app multiple times when I’m trying to listen to music… So before the community bot comes at me with that asinine suggestion I’ll just shut it down now.

THIS NEEDS A FIX!