Earlier quoted context omitted.
It's not an Apple issue. Works perfectly when you use a Mac + AirPods. The issue is when you try to use Windows. All bluetooth headphones I've tried (with microphones) sound horrible with Windows, if they work at all. The walled garden has a few advantages...
Airpods do not have better duplex audio on MacOS. The problem is that AAC cannot support high-quality recording and playback at 330kbps, so it has to degrade the quality of the recording stream to fit within the Bluetooth bandwidth. MacOS might default to using your laptop's microphone, but that's something you can also set up on Windows. Hell, it should be the default on Windows as long as you have AAC support insta…
The point isn't that there's only so much bandwidth for mic + headphones, the point is that the bluetooth stack on Windows just doesn't work. I tried connecting multiple bluetooth headphones (Airpods, Beats, Sony) to a new Windows 11 computer (Microsoft Surface). I only got one set paired and it defaulted to the headset profile immediately. It was horrible. The others never connected or the connection was unreliable.
The process was so bad, my son recently bought a set of wired headphones just to avoid the entire issue.
If you've never been in the Apple garden and used headphones + device, it's a night and day difference in experience.