For heavy Quest gamers, it's standard to strap a battery pack to the back head strap, which also serves as a counterbalance to the weight of the headset. Based on frequent comments on Reddit, players are going strong for at least 4 hours. More an issue might be that VRChat is more limited -- at least that's what users are complaining about. I've never used it so I wouldn't know either way.
I got the off brand earbuds but haven't tried them yet. I also had to get another cable for side loading because for some reason it wouldn't consistently work with the cable I got that has the detachable end piece that goes into the Quest. It would charge though.