iOS 15 poor car bluetooth performance with Apple Music - UPDATE

This is an update to a previous thread I had already started. To quote the previous issues:

For reference, I have a Honda Civic 2013 and iPhone 12 Pro.

• Apple Music consistently has the “Resource Unavailable” message pop up, even when disconnected from Bluetooth.
• If I skip songs (whether I use my car controls or skip from the iPhone) while connected to my car, ever so often the volume of the music goes very low. The volume slider could be all the way up on both my phone and car, but the only fix is when I skip a random amount of times, or some other system sound occurs.
• FaceTime calls transferred from my car’s Bluetooth to the phone will immediately cause my phone to freak out and re-output sound from my car, and furthermore will start playing music that I can’t stop or quit.
• FaceTime in general has horrible connectivity performance and failed calls while connected to Bluetooth in my car.
• There are so many other bugs that have occurred but they have piled on so much I forget their specific nuance. I have reported most of what I can remember on Apple.com/Feedback.

UPDATE ON iOS 15.4:

The problem continues to persist but has become worst with this newest update, now the volume readjusts itself to be low even when I am not skipping the songs myself physically. To reiterate, the volume slider does not change, it is a software bug that I can only fix by pressing buttons on the iPhone itself (not the car).

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