IIRC Android uses a regular Linux Bluetooth stack.
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.
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.