Thanks for a useful article. We are concerned about this topic too. And have some thoughts to share. Speaking about the RN disadvantages in comparison with native apps:

1. Yes, everything that interacts with the device functions (camera, gallery, maps, etc.) is implemented in native languages - Objective-C / Swift and Java. Then you need a wrapper to use them via JS.

2. It’s rather yes than no. It's not so easy to interact with native modules and libraries, you need to have experience working with XCode and know a little about the way the Android project in Java works. However, it greatly depends on what functional the application implements. If the application is simple, then minimal knowledge is enough. If there are many third-party modules and libraries - you need more knowledge, respectively.

3. You can run the code on both iOS and Android. Again, it all depends on the implemented functionality. Sometimes it happens that some module or library does not work for one of the platforms and you need to configure it additionally or even change it. In addition, the layout issue - sometimes the customer wants the application to look like native. In this case, you need to use material design for Android and flat design – for iOS. However, the logic will still be the same, so most of the code can be re-used.