iOS safe area insets for both portrait and landscape before adding a view to the hierarchy?

Question

For various optimization purposes, I want to get the device's max display size without the safe areas for both portrait and lanscape.

I can use the UIWindow's safeAreaInsets, but that only gives me the current safe areas, not the one for opposite layout (assuming there is only portrait and landscape).

I had a look at UITraitCollections (I really thought I could achieve it with it), but it seems like a dead end.

Anyone can help me with that ?

Thanks!