My issue is similar to this one, Bootcamp says Disk Could Not Be Partitioned on Catalina Version 10.15.2
I'm on a 2019 iMac i9 27" with a 3TB Fusion that's been formatted with Catalina and APFS from the beginning, but I have successfully installed Bootcamp and removed it. Now I'm trying to play games that don't work in a VM and want it back.
Bootcamp is failing to create the partition and corrupting the APFS container as it unwinds. Actually, it's creating the partitions but gacking at some point. The question above has the fsck_apfs commands I've been looking for, but I'm looking beyond that.
What if, prior to reloading, I created the APFS container AND a smaller HPS/NTFS/FAT32 partition for Bootcamp Assistant to use? A "sacrifice" disk if you will.
Does it matter if the partition is created first, in the first sectors of the drive or at the end behind the APFS container?
This time, I plan to only do a MacOS install and not a recovery to test if this works. If so, I'll either restore directly to it or blow everything away again and do a full restore from the ground up with the extra partition.