There is no class that implements QCameraViewfinderSettingsControl2 interface on Android. It means that viewfinderSettingsControl2 member of class QCameraPrivate is always null, hence such methods like QCamera::supportedViewfinderSettings will always return empty list.

This is already mentioned in https://bugreports.qt.io/browse/QTBUG-46470 but bug is closed. I think it makes sense to open this feature request for tracking purpose, e.g. to know if somebody will fix it.