Also the old Cordova equivalent and Kivy. Take mobile development and try to shoehorn a browser-based solution (they don't want) into it. Now you've got two problems and not enough expertise available to help.

NativeScript is not react-native

Did they have JS _AND_ React experience beforehand? Or did they just pick RN because it was the cool thing on the block?

I foundered on my first attempt at an React app (side project) coming from a C,C++,Java and non-React JS background, but the second one(professionally) after I've had exposure to some React got released and an fork of it is still in use today. And the company I work with has 2-5 other apps out for customers using RN/Expo (thanks to the positive experience I had).

We're also strict about using TypeScript though so we're not chasing basic type bugs (since debugging is a tad weaker with RN/Expo even if it's usable if shit the fan only occasionally) and we have plenty of React experience outside of it, biggest "quirks" are often RN/Expo upgrades if we haven't maintained things in a while (the oldest app used a relatively early version of Expo though) or platform specific notification crap (that I've heard is painful regardless of Expo/RN).