How do we handle navigation when integrating react-native to an existing native project

I am trying to integrate a react-native project to existing native projects(android and iOS). What are the different options available for acheiving full navigation from native to JS and vice-versa with a single navigation control.

1. Say i want to add just a single .reactNativeActivity and render all of my ReactNative activity in it. Now this react-native activity has its own navigation(say react-navigation), i should be able to navigate to native activity. I have done this creating native modules. This is solved.
2. Now how can i navigate from an native activity to this .reactNativeActivity to a particular screen inside it.

I see that we had native-navigation library by airbnb which isn't being supported now. I can still add all the react native screens as individual activities which will still solve this but i don't see that it can be maintainable. Can somebody guide as to how to proceed with this and how do others generally do?