Got a Vive Cosmos 2 days ago and it crashes Unity whenever we try to use.
Just create an empty project, activate XR Plugin and OpenXR, restart the editor, add HTC Vive Controller Input, transform main camera into XR Rig (the standard for creating an Open XR scene, nothing fancy).
Click play -> Crash.
SteamVR is working correctly, and in the Vive Console, OpenXR is set to Steam (not Vive).