Which GoPro? The 7, 8 and 9 will connect, but only the 7 has "full functionality". On the 8, you can start and stop video or take a snap, but when you try and switch modes between video, picture and timewarp it just goes to picture and stays there. Doesn't bother me as I just use video so start and stop it ok. The 9 is worse in that it exhibits the same mode switch problem, but then adds another problem in that while it can start recording from the bike controls, you can't stop it again. Not great.
Pairing everything effectively was problematic for me, but I discovered that the order was important. I had to clear all pairings between my Sena in my helmet and my iPhone, and any pairing I had already made to the bike, then pair headset to the bike first, then phone, then GoPro.