Red and Green are not bad (nobody would understand Yellow/Blue but I'd see it great 😎) but what works well is to supplement that with a shape change so perhaps use a symbol that inverts or a slightly larger circle that is red and open and green and filled in.

That really helps out people like me.

I'm not sure this will come out on PeakD but these Emojis are good:

🔘⭕️🟢

Also pressing the Green to disconnect without a bit of a warning or a pop up is annoying. I would expect pressing on that tiny symbol would give me a screen with information about HAS sessions and only there the option to disconnect. The explanation you've given here I would never have guessed or stumbled upon without reading somewhere.