I use Linux and have problems with Bluetooth-connections to my headphones all the time. Looked into BlueZ to see if I could file bug reports or patches but it looked like a hot mess. Running the Android stack on Linux might actually be nice!
Also WRT your problems: In case you did not yet, switch to Pipewire. When I did that a couple of years ago, my BT Audio experience went from bad to really good.
https://chromeos.dev/en/posts/androids-bluetooth-stack-fluor...
For example, I have JBL headphones, that work perfectly in the A2DP mode; but switch to HFC for the mic, they will work for a few minutes, then drop off and stay that way until reboot.
That's with Ubuntu. With Android, no such problem.