I’ve actually worked on a few VR projects in Unity and we have a couple of rules we followed.
Either stationary location and the movement is within the boundary, no large drops or sudden movements the user doesn’t control. Use teleportation like in the Mixed Reality portal or SteamVR home. Avoid movement that the user doesn’t control by actually moving or teleporting.
If you need to move between points, fade to black, move and then restore the view. This would very quickly, like .5 seconds.
Other ways I’ve seen is in Elite Dangerous, they have the cockpit so you are sitting still and the world outside is moving. Minecraft offers a mode with a frame, almost a TV-like view into the game. This totally eliminates the feeling of sickness. You can jump into the game and it takes a lot of getting used to but is more immersive.
It’s a trade-off really.