Have you checked the sound volumes under settings, Sounds and vibration, Volume? Adjust the sliders to suit. There's also a volume limiter accessed on the volume screen using the three dots at the top right-hand side. Hope this helps.
Ye I have been through every option I can even in developer options. The blue tooth is also very quiet when played though devices nearly half the volume of my note 10plus really disappointed with the phone and contemplating returning it
I thought you might have. I'm afraid I can't be of much help, only to sympathise. I think the same as you. I'd reset it and if that doesn't work, return it. Good luck.
