I agree that react-native could work the best, but why are you so determined to develop an app like drop? I think it's better to come up with something new, and it'll get more recognition. Nowadays, many people decide to learn japanese with anime, for instance, and I think it's worth learning more about such methods and combine them in your app.

Drop isn't a particularly complex app. You're not relying too heavily on native components of the phone either.

The big things here are a very custom UI and a lot of animations. React Native, and Flutter especially, lend themselves well to these types of use cases.