I had this issue before but I was able to resolve it by troubleshooting Xbox steps from Mojang and Microsoft.
I got a new Xbox series S and I get the error:
Can not sync your worlds. I got this after an update on my Xbox one and removed account, restarted, uninstalled, removed all local storage but the error still occurred.
I save my worlds multiple times each month and even was able to open it on another Xbox so I know they were saving to the cloud.
Now I can't get any worlds to load even from the cloud. I know they aren't stored locally. Anyway Microsoft or Mojang can look at this on the server level, maybe even pull previous version.
I've save my world named Primary multiple times as copies. Hoping it's possible to go into server and pull previous version

Opened a ticket with MS/Mojang and they stated they are rolling out newer updates. According to the link listed below, I have the proper App Model

https://help.minecraft.net/hc/en-us/articles/8386720596365-Minecraft-Performance-Update-Details?fbclid=IwAR3JZL7-qfdMs8rcJK0QvU0ZUT-21QOOKedxGvX0pRBd8qR-EgLmr-O1j_c