I am permanently getting the error that the RGB Camera is disabled. Even though all permissions are given, Power Mode is disabled (both, Nebula AND phone settings).
Ok, I managed to solve this. The powers saving mode some refer to is not the Android setting its in the Nebula app. When you enter the app and have to chose between MR space and Air casting on the top left corner there is your user profile, click on that and go Settings > Power Saving Mode and turn it OFF. This is not intuitive at all.