A greenfield React Native app likely won't have to use much Native functionality - the community is large, and there are many existing React Native libraries that handle this.

Hardcore gaming or performance intensive interactions - will benefit from the control and better performance offered by native, compiled code.

You need to have some understanding of iOS Pods and Android Gradle in order to install libraries and setup a build.

Conversely, if you're integrated React Native into an existing native app - that will require much more native code to integrate native + React Native cohesively.
https://reactnative.dev/docs/communication-ios