How to use different scenes in an AR app?

An AR app can get pretty big, so I am hitting the Google Play store app size limit. To avoid this, I want to split the app into a small startup APK and extension files (obb).

To reduce the APK as much as possible, it is recommended to use a small startup scene (which e.g. only shows a splash screen) and then switch to the actual content scene on startup (using SceneManager.LoadScene()).

However, if I try this in my AR app, the scene switch takes place, but the AR camera is not being...

How to use different scenes in an AR app?