Increasing those two numbers to 180 (from 90) and 360 (from 45) speeds up the rotation and masks the stutter. I've experimented with changing those numbers and I don't quite understand how they interact, sometimes with no effect past a certain point. Anyway, the increased speed is the speed of turning in the Team Beef Doom VR mod, which is okay for me (and others, apparently, since I've never seen complaints about it on their reddit or discord forums). The stutter is still there in GDevelop if I really look for it, though, so maybe it's something inherent in GDevelop's rendering.
Happy you pointed me to that event sheet since I was also easily able to implement sprinting with the left trigger. We'll see where this takes me.
Do exported games work on gd.games in VR? Have you tried it?