I have BottomBar added in ComposeActivity. BottomBar is responsible for showing 3 composable. I don't want to add ModalBottomSheet to Activity instead I have added ModalBottomSheet inside 3rd Screen Composable. When ModalBottomSheet is invoked it is displayed above the BottomBar. How ModalBottomSheet can be displayed when Call to Action is done from 3rd screen Composable and it should be above BottomBar.
Any help will be appreciated.

It should display over BottomBar and on Bottom.
Just Position your ModalBottomSheetLayout on top of the Scaffold component.
Example:
and call bottomSheet from NavHost.
Also you can hide Bottombar with action from screen but its long way;
*it may vary depending on your component child structure
Screen:
NavGraph:
Scaffold:
BottomNavigationView: