Wait is there a device that can do stereo AND mic? I’m not aware of any and I’ve searched long and hard. AFAIK, there is no way it is possible with the current BT spec. Are you saying your Apple headphones can do that?
I think it’s mostly on the device side. Both sender and receiver have to have the codecs available. TBH, I just recently learned you can go into iOS Bluetooth settings and change the device type to “speakers” and use your computer (at least if your computer is running Linux) as a speaker. It’s freakin magic.