Check out GoodOrBad - Simple Meal Logging on the stores, it’s fully React Native with some little native code (push notifications, etc.)
2. The app starts with a launch image (the logo in the center), which then fades away to show another launch image (with the logo on the top half of the screen): https://imgur.com/0n3Zbof (probably because ReactNative must load the JS bundle before it can show anything)
3. The login screen of the application fits on the screen, yet it can be scrolled up/down for seemingly no reason. The amount you can scroll feels suspiciously close to the height of the iOS status bar: https://imgur.com/P6conGz (probably because ReactNative sets the UIScrollView's contentInset incorrectly)
4. Text fields / buttons look like on a website.
5. When you navigate back from the login screen after a failed login, there's a brief moment while the "Unsuccessful login with Facebook" message is visible, which then quickly disappears: https://imgur.com/hTTKbIt
Sorry, but it feels like a webapp to me. Though it might be perfect for your use case!
Update: I've found some other issues:
6. You can't interact with buttons (e.g. "Next" button on registration) while the keyboard is visible: https://imgur.com/dpy5xv8
7. The first time you switch to a tab, it's completely empty, then suddenly the content pops into place: https://imgur.com/JKaCJED
8. Tapping on the search button makes the content of the previous page jolt against the top of the screen while navigating to the search page: https://imgur.com/BJDYvda (focus on the panda)
9. The "sidebar" menu feels very out of place on iOS. Also, when you select e.g. "Settings", the content on the right does a very weird fade/slide animation: https://imgur.com/ChNzvwW
10. When you switch between two non-adjacent tabs, the viewport slides over the in-between tabs too: https://imgur.com/BZFU0Sv
1. This can easily be fixed with a module, however time pressure didn't allow for additional "tweaks"
2. Same as 1.
3. Using Scrollview for this, since some android devices with smaller screens can make the Login screen look very ugly and small, so in that case scroll looked better.
4. Do they look like or feel like ones on a website? It is by design, but interested to see how you feel about the fields as a user (although we don't support the app anymore)
5. Caused by implementation logic
See UberEats, the former Airbnb app and others using ReactNative that can seamlessly deliver native style UX.
2. The Airbnb and UberEats apps were written by expert native developers (I happen to know a few of them), using some React Native.
You see, expert native engineers can deliver quality apps using native frameworks. And surely, if they look into React Native, most of the time they can manipulate it from the JS side to get the desired outcome on the native side. The middleware is a hinderance for them as it gets in their way of implementing what they want in the first place.
It's like building those ship models in a bottle: if you know how to build the ship, you just have to learn how to do it through the neck of the bottle. If you don't know how to build it in the first place, well... that's a different story.