I literally can't do anything correctly anymore, I can't load worlds, can't create new ones, can't access Realms, can't change settings, can't select things on the store, can't log in to Xbox live, nothing works, it's all broken since yesterday's update.
Have you tried a full reinstall of the game?
Backup any data you don't want to lose, then try the following:
Backup your MinecraftWorlds folder (if you want to save your worlds) (Device storage > games > com.mojang > minecraftWorlds)
Uninstall MCPE
Delete the com.mojang folder (Device storage > games > com.mojang)
Reinstall MCPE
Run MCPE and if it works restore your MinecraftWorlds folder
Sometimes a clean install of the game will help with these kind of issues.
Please back up any data you wish to keep and uninstall then reinstall the game. You might find following links helpful:
How to Back Up Worlds
How to uninstall and reinstall a game on Windows 10
Also, please check that your system drivers are all up to date before reporting back.
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