Alexbaron309: 1.21.101 did not fix this issue for me either. I still get the error. I deleted all other worlds except for my main which is 990mb, but it will only let me save locally.
I updated to 1.21.100 and still have the same issue
On my Series X, I deleted every save except for my main save I've had for 7 years which is ~850mb. I still get this message when saving after the most recent update.
I’m still having this same issue. I’ve deleted all other worlds from my Xbox, I have only the one world which is 1.0GB. I’ve cleared a lot of cloud save data from other games, I have nothing left to remove and my game hasn’t been able to back up to the cloud in over a year now.