Wouldn't classify this as a crash, I would have to manually close software, then get unexpected error occurred. I waited once about an hour and no menus were ever accessible, I walked through nether portal and it never rendered nether, once reopened my player was in the nether, so realm was still processing movement.
Turn off AUTO SAVE TO CLOUD, its attempting to back up data, huge bug in this feature for minecraft but just turn off auto save to cloud under data management. I can play again. I created report last night.
I hate this but I'm relieved a bit to know its not just me. It was happening for a day or say, then I was able to play for a an hour or so one morning, looted a tricky trial then got booted. took a good 30 min to log back in, where the it didnt save the progress and I played maybe 5 min and that was last time I seen my world.
godspeed mojang