Yes it is still popular. Take a look at the showcase who is using it - Amazon was just added

Libraries have always been a unique problem to React Native. A lot of the time not maintained, and can be low quality too - like half baked re-implementations of existing native components, skipping the whole ‘native’ part

There’s not really another cross platform mobile framework in the same league. Flutter exists, and has its positives, but will never be an amazing experience on iOS. They don’t use native components, and the native components can access OS stuff not accessible by people other than Apple