Except for the "headphone" versus "headset" mode dichotomy that is inherent to Bluetooth, all those other issues are due to stupid product decisions that most OSes do to themselves independently on the same way.
If you use Linux + KDE, you can still use any microphone or headphone, many at the same time, or in whatever mode you want.
It used to work on kde/plasma 5 at some point. And after a minor version update it stopped working.
Now the mic of my headset doesn't work because KDE insists that only the high quality sound output without mic is available. The mic + low quality output is gone from the settings.
Lucky for me this update also brought proper handling of the stereo positioned noise cancelling microphones on my thinkpad. So now I can actually enjoy the luxury of built-in microphones that work. Until the day it wont I guess.
I am using pipe wire. The option to select the handset mode is gone! I can only select the various output codecs with my increasing quality. But not the mic & output mode. It's gone from the list...
> If you use Linux + KDE, you can still use any microphone or headphone, many at the same time, or in whatever mode you want.
This doesn't really seem to respond to the problem. The problem is that I'd like to use a single bluetooth device that includes earpieces and a microphone. That doesn't work, because of the headphone-headset mode dichotomy. As I replied to another comment, using multiple devices would be a solution to the problem. It wouldn't be an example of the problem that I want solved.
Bluetooth is apparently incapable of simply delivering an audio stream to the earpieces while accepting one from the microphone. This is a baffling design. The assumption appears to be that there will never be more than one source of audio for output. But that's crazy.
If you use Linux + KDE, you can still use any microphone or headphone, many at the same time, or in whatever mode you want.