Poor Sound Quality since iOS 16

To set the scene; for years now I have primarily listened to audio in my car using my iPhone via bluetooth. Years and years, multiple iPhones, no problems.

I started noticing after upgrading to iOS 16 on my iPhone 11 ProMax that my sound was degrading while listening to it. It would start out OK, but as time went on it sounded more and more muffled and I had to turn my stereo up louder in order to hear normally. ALSO I could start out with sound playing normally, but if I say - stopped driving and went into a store - and then came back out and resumed listening the sound would then be muffled. Always restarting the phone helped, but always the problem returned. I figured it was my phone which was old and tired so I upgraded.

NOPE. I'm having the same issue with my very much brand new, just got it a few days ago iPhone 14 ProMax. This is now completely unacceptable. Any ideas what's causing this and how to resolve this issue?