Hello Txori.
So I read in the comments that you are duplicating the camera.
I actually tried that myself with a small three.js vr game.
That method is not going to work on the quest. Just to completely sure, I installed the early access version from the playstore.
Unfortunately it does not work, as I expected. It starts, but the controllers are not mapped correctly (which makes sense),
screen is not full screen but windowed, and when enabling vr, it just adds an extra screen next to it.
It's a shame, because this would have been a great game with a nice retro feel, a bit like Minotaur Arcade on the psvr.
Kind regards
Tjoen