Default camera?

I would not recommend disabling positional tracking, but if you want to have a seated experience like a car driving one look into the Set Tracking Origin node it allows you to manually place the camera in your Pawn and have that be your default position

If you don’t want positional at all see
Disable Sensor Unit - XR Development - Epic Developer Community Forums or
Locking Vive HMD height (z location) - XR Development - Epic Developer Community Forums