I've been working in VR and AR for nearly a decade. I've even built my own headsets. The experiences that make people sick are always low framerate. I've put people through experiences pegged at 90FPS for hours at a time with no nausea.
You need foveated rendering to start with but im sure you know the rest. If you want VR, well you need actual VR. Its not enough to trick your vision superficially. You have trick the whole system. I digress.