This seriously needs to be solved. I can report the very same issues listed by OP. Please, this is a high priority bug.
I have the same issue. Can't load any save file anymore on my Switch since yesterday. I really don't want to lose all of our worlds. Getting the same error and also a very long loading screen when starting the game. Help me please!
This seriously needs to be solved. I can report the very same issues listed by OP. Please, this is a high priority bug.