See a LOT of searches on various sites, including here, related to people who want to use their Bluetooth headphones, get stereo sound when using their applications (Teams, Discord, etc .) AND the Mic from their headphones. Without using a cord between the bluetooth headset and their computer, without using a separate mic, with the option of continuing to listen to music while in a conference, etc. I see many different answers, none of which match MY results, and I have spent quite a few hours trying all the various 'solutions' I could find.
Have tested this on multiple computers, with Windows 10 and Bluetooth 4 as well as 5, with Sony WH-1000XM4, Apple Airpods Pro, Apple Airpods Max, and cheap headphones too. As soon as you select Mic, the headphones switch to Hands-Free AG Audio and sound from other applications stops while sound into headphones goes to AG Audio (poor quality.) So it works, both mic and sound, but at mono quality.
Of course if the device is a laptop you can use the laptop's mic, and use the bluetooth headphones in stereo for listening only.
I take all those headphones and connect them to my new desktop computer running Windows 11, and ALL of them work fine. Sound plays in Stereo, music keeps playing while in chat (Discord/Teams, etc.) if I want, and mic works perfectly fine too. THIS is what I wanted, but cannot do on any other device not running Windows 11. There is not even an Hands-Free AG Audio setting I can select on this machine.
While there are many variables in play here beyond the OS, the fact is in Windows 11 it works while NOTHING I have done in Windows 10 gets it to. Your mileage may vary, but this is what I see.
My question is, why has Microsoft not really clarified the root cause/solution? I can only assume it's because of the fact that there are indeed countless variables in play here across operating system versions, bluetooth devices, drivers, installation configurations, etc. Makes me glad I'm not trying to build and support Windows, but since I also on a Mac I'm glad Microsoft does as the two are quite different (and last I checked, the 2019 MacBook Pro ALSO had this issue with bluetooth/stereo/mic.)