Well, the first resource I would recommend you is my upcoming book by Packt Publishing, "Professional React Native", but it's due late January next year :) . Now jokes aside (the book's real by the way :) ), the easiest way to build a iOS/Android/Web app with React Native is to do: npm install -g expo-cli expo init some-project cd some-project expo eject

You might have heard of Expo, but trust me, stay away from it. Expo highest value is that it's an already pre-configured 3 platforms environment, but if you don't eject then you're vendor-locked to what Expo has to offer in iOS and Android, which is very poor compared to going full React Native on these platforms, they can't even handle Google Sign In properly and by the way, even if your app is 10 lines of code your app size will be over 40 MB if you don't eject, yep it's that bad, plus the performance is regular and the loading times slow, not to mention that you're stuck with their build service which the free tier makes you wait for hours for a free build slot. It's important to note that when ejecting you don't lose the Web, you simply do expo start --web to start your dev environment and expo build:web to build a static website that you can serve with any web server. Regarding state management, don't bother with "lifting state up" philosophies mixed with Context API to manage your state, lifting state is a great pattern and helps your codebase, Context is great to avoid prop-drilling, but NEVER mix them to achieve app-wide state management, for that, simply go for Redux or MobX, the hype is all about Redux, but I consider MobX far better in many aspects. However, as you're getting new into this I would recommend you start with Redux AND PLEASE grab yourself npm install @manaflair/redux-batch so that you can batch updates and don't bring your app to a crawl. Forget that "connect HOC" thing with React-Redux, don't bother for a second with it, go with Hooks and useSelector and useDispatch and the likes, it will make your code SO much cleaner and smaller. Adopt clean and new Hooks philosophy, avoid writing class components as much as possible and write function components augmented with Hooks.

Spring is generally more an enterprise solution, while I see Django being more startup oriented. Django is lightweight and fast (development time, not runtime!). Spring seems to have more focus on microservice architecture than django, if that matters to you at all. Starting your project in Django, it automatically creates a backend 'admin panel' for you to use and customize. You will not find this in the more serious Spring Boot.

Though Java is a strong language and basically the first language to be used in Mobile Development (Android), the framework Spring Boot is not as modern as the Django framework which is based on one of the most popular languages today - Python. Moreover the Python language is far more simpler in syntax and just as powerful as Java. However, Java has scaled up it's performance and the Spring Boot framework can support dynamic web development as well as android development. Whichever way you choose to go, there will be no regrets - trust me.