If you refer to music streaming via BT, I just tested it with YouTube - streaming is separate program that’s added. I believe on the last position if you have more than just autosense. And then with volume down long pressed you switch between programs, effectively this means that you should click only once to be able to go back to ausosense. I don’t have custom programs yet, so I can’t confirm where it puts that exactly, for TV connector when you put it in manual, target says it’s gonna go to the last position, that’s why I assume the same here.
And Youtube paused when I switched with that button.
Edit: but it does only that, no resuming when selecting it again. So I guess, you’ll still need phone for that.
I’ll check in target if I can see something about that, but I don’t recall seeing decent ability to program those buttons, only turn on or off what they had in mind and pause/play wasn’t among them afaik.
Edit2: use app and switch on HA, then you’ll see exact order.
Program change to autosense will work on volume down only if both up and down are set up for program change, of course.
You can have mute/unmute mic on volume down button, but afaik that’s it, no media playback controls.