Honestly, the whole experience in the menus in this game is hot garbage. I spend more time trying to get my kid into his realm than him actually getting to play. If I ever programmed anything this bad, I would have been fired.
Literally it will
1) freeze on the initial loading screen.
2) Freeze opening up the list of worlds/realms
3) Freeze on trying to load into a realm
4) Freeze randomly throughout these menus anywhere when I click on something
And this isn't isolated to a single Nintendo Switch console as I have 2.
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Thank you for your report!
However, this issue is being tracked in MCPE-109371.
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Was plagued by this problem for the past couple of weeks. I have been able to fix it if anybody wants to try it out for themselves! Backup your save data, delete the minecraft software, power off the console, remove the SD card, then reboot. Reinstall minecraft without the SD card and set up your game with login. Inserting SD card after the fact has had no Ill effects for me yet. Good luck!