[pedroma]

Also wondering. Does a headphone like that even exist?

A BT headphone that can stream from 2 sources at the same time, mix the audio streams together, have the controls play/pause both sources at the same time, only use voice assistant from a primary source.

My guess is it's just too complex, and maybe there's no BT chip that can do 2 high quality audio streams at the same time that fits the power requirements for a 20hr headphone experience.

What I do is use an A2DP sink that sort of does this. But I need a Windows machine that pairs with all my BT sources, it mixes the audio output from the sources (along with the Windows audio), and outputs it to the default audio output. It's quite nice if you don't like taking your headphones on/off all the time.

[ehsankia]

I don't think there's mixing, but normal Multipoint keeps both connections alive, and switches to whichever has active audio coming. It can be a little annoying if you have notification sound on your phone stealing the attention, but generally it works pretty well.

But again, simple multipoint support seems to be pretty rare. I think the newest WH-1000X M4 finally added it, the Microsoft Surface headphones also have really good ones, and that's kinda it.

Some devices like Samsung instead use a fast switch, I think that's what Apple is doing here too?