When you move in the VR, the brain visually perceives a movement, but not the inner ear, which is responsible for registering bodily movements.
One theory is, that the brain thinks we are poisoned and we are hallucinating and that's why we get sick and we have to vomit in the worst case.
This is inevitable i think, i read this years ago and i hardly believe there can be any solution. This happens also for other things and you basically have to live with it.
Is this really still a thing? Even with those new devices? It's hard to believe! Now I know why VR isn't that popular right now (also the fact that there's not much content around and good devices cost a lot)