How to navigate right between screens with bottomBar and others

Please, help me to understand how to do it right.

I have an app, which represent a screen with bottom bar with 4 tabs (1st layer). From this tabs we can enter other screens (2nd layer) without bottom bar. This organized very simple, Scaffold with bottom bar and navigation host inside it. To open screens above 1st layer without navigation bar I searched and found that I can just hide bottom bar and then open the screen above.

This is good, but on slow devices an ugly animation happen when 1)bottom bar is going down (user see the old screen without bottom bar) and 2) new screen appears. This is not pleasant, but.. ok. The second thing that I cannot stand is when in a 1-st layer screen I have a ModalBottomSheetLayout. When it hidden - it hides right behind bottom navigation bar and when I am going to new screen bottom navigation animated down and... here you are - the ModalBottomSheetLayout, and only then the second screen come to the place.

I wonder, may be I understand everything wrong and the new screens shouldn't be organized like this? How to set up navigation and scene like before compose we have a main fragment with bottom nav bar and open fragments on the top?

The example of the code I am talking about can be found for example in app nowinandroid, I think this is very common case.. As I see they also just hide bottom bar when needed.. @Composable fun NiaApp...

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