Saving my world is impossible.

I have a world on my Android device that I can't back up at all. The problem is that I'm running the beta version, and the world file is located in the internal storage. The system won't allow access to the folder, and the game itself doesn't let me export the world. I even subscribed to Realms, but it says the service isn't available in the beta version. Leaving the beta program doesn't help either, because uninstalling the app deletes all the data. It's a huge problem!