Migrate from Oculus Integration to XR ALL IN ONE.

I'm doing the same thing and unfortunately, it is not an easy process.  The headset stuff is similar, but the interactors, hand presence, and hand tracking are fundamentally different.   The best way I found was by creating a copy of my scene and delete the old headset and interactors, then create a new gameobject headset/interactors with the buildingblocks.  I then test to see what stuff works.  I flip back and forth between the old scene and the new scene to figure out what things need changing.