I could never get a listenable volume (has to be at 100%) from my phone playlist through the car's (stock) audio; that same phone plays with great volume on another car, so it's not the phone (Motorola). That other car is 32 years old, so no "fancy" tech. I'd think it either it works or not, but this is strange. Am I missing a setting?

 

With my iPhone 14 Pro, I have to put the phone volume on max and I’m still over 2/3rds of the available gain/volume on the radio to listen to music at a medium sound level. Sound level is subjective but I hate loud music so I’d say that at 2/3rds way up, the volume is reasonable and not obnoxiously loud.

I’d chalk it up to the fact the stock speakers are absolute trash. The radio volume might have been derated to avoid blowing the speakers.