What approach did you go with at the end?
I am asking myself this question for new navigation 3 lib...
AppNavigator in app module seems to be a must, but I think it is overkill to have FeatureXNavigator for every module.
I am leaning towards injecting AppNavigator to every composable (Screen) same like for GlobalViewModel for example.
The other thing I would like to do is to have standalone navigation module with AppNavigatorInterface, which app module will implement. The point being to easy swap out nav3 with whatever come next.