I'm on a Alcatel Joy tab, I've gotten an issue after the nether update where the Main Menu will not pop up at all. I've uninstalled and reinstalled and it fixed it for a short time before I was unable to load into a world, it would crash. Have me exit the game. And when I relaunched the game the Main menu will not pop up. If I uninstall and reinstall again it's completely normal and I can start in a NEW world but not on a pre existing one from 1.14. after I exit the app and relaunch it. It's the same issues of the main menu not popping up even after long periods of time, this has happened to me before but this was when I joined the beta tester program for 1.16. I ended up quitting and went back to normal Minecraft. I'm currently not a beta tester so I have no Idea what the issue is. 

short story

Make world in 1.14 with bunch of progress

Updated to 1.16

Main Menu doesn't load