Aslam Mohammad

I don't think this is a fair comparison as both are different ends. Flash is a microframework of Python, and React is a UI library of Javascript. Try building the app using React, as it has a rich ecosystem around visualizations. Just a quick thing to say, if you want to develop a good application you have to use Javascript in any way.

I would definitely recommend Node over Flash and Django especially for the requirement mentioned above, Kick-starting with Node and using any front-end framework like Vue, React would make your application catch up process more easily. For this kinda requirement bringing Django would make it a bit complicated as Django is more like Angular in the front-end full in terms of wiring up and getting started.

Node.js is better for this kind of requirement as it's written in Javascript which is more simple and vivid to start with simple CRUD application. Java doesn't stand back but does require a lot of configurations, and technical insights involved. Although both Java and Javascript holds your back coming to mobile apps with Android development using Java/Kotlin and native apps development using React Native.

You could apparently go for both Node or Django but I would recommend choosing Node as you're building a video streaming app and the biggest video streaming service Netflix used Node in the production.

IMO, Next.js suits best according to the requirements mentioned. Express.js could also be used but as it's a backend-heavy framework I don't think it is required here. I would recommend using Express.js for applications that have more significant use cases from the backend.