The fourth time was during this spring lockdown with my current phone that supports more VR apps. I spent much more time and went into worlds in first-person mode. I experienced motion sickness from not moving. I didn't know it was possible to get motion sickness from not moving but that is what happened. My eyes were telling my brain that I was walking along a ravine but my nerves were telling my brain that I was sitting down.
I think a big breakthrough that would overcome this problem would be a rig that allows you to walk without moving anywhere, like a treadmill or frame with ropes that you hang from so you can walk in virtual reality in a more natural way.