Hi,
are the scenes loaded async?
do you have a loading screen during the loading?
Maybe have 1 camera that persists (and have no camera on the other scenes)
or does the scenes only have the controllers and camera?
if so, maybe have both controllers in 1 scene and use the same camera.
and enable/disable the controller used/not use.
this way you could also make a 'transition' from 1 to the other
for example smoothly move camera from 1st person to 3rd person.
you can have a object with all the camera positions used and make it follow the player (or set as child) and make the camera follow (and rotate) the current used position object