Well, I guess you were lucky.
I've done all this and more.
I've even been to the car dealership and they have replaced the head unit in my car under warranty in an attempt to fix this. No change.
FWIW it's worth to help others:
iPhone 15 Pro
iOS 17.2.1 (current)
2013 Porsche Cayenne with standard PCM (head unit) - car still under extended factory warranty! Which has been replaced by dealership.
I have tried every reset, disconnect, erase, rain dance and voodoo doll I can find and get momentary improvement.
I believe it's a bad hardware component batch as not everyone is having this issue.
And that's why it hasn't been fixed by software updates.
I am tempted to buy another iPhone and see if I have the same issue. If I do, return it under my 14 day period.
If it works, I'll sell my original 15 second hand and take a loss of a few hundred bucks.
It's a shame Apple is more interested in selling recurring revenue service than producing excellent and innovative hardware.
It's been a notable decline since Jobs & then Ilve moved on.