Boot Camp can't partition drive despite sufficient storage
Hi,
I'm running an iMac 14,2 with macOS Catalina 10.15.7. I recently upgraded it with a Samsung SSD a few months ago and decided to install Windows through Boot Camp. It booted into the Windows 10 setup, but I encountered an error while formatting the partition to NTFS. I then restarted back into macOS, removed the partition with Boot Camp assistant, and then tried to reinstall Windows multiple times with different flash drives, etc.
I found a possible solution to the error which involved resetting the SMC and NVRAM, so I was going to give that a go, but now Boot Camp won't even partition my internal drive because of insufficient free space. This is perplexing because I have almost 650GB of free storage. I'm wondering if this is a problem with fragmentation or leftover, "hidden?" partitions from my failed attempts to install Windows. I would love to get some clarification on this. Thank you all so much in advance!
P.S. my new SSD is working fine, here are the results of "sudo fsck_apfs -n -l /dev/rdisk" in case it helps:
** Checking the container superblock.
** Checking the EFI jumpstart record.
** Checking the space manager.
** Checking the space manager free queue trees.
** Checking the object map.
** Checking volume.
** Checking the APFS volume superblock.
** The volume Macintosh SSD - Data was formatted by diskmanagementd (1412.141.1) and last modified by apfs_kext (1412.141.2).
** Checking the object map.
** Checking the snapshot metadata tree.
** Checking the snapshot metadata.
** Checking snapshot 1 of 1 (com.apple.TimeMachine.2021-08-16-163638.local)
** Checking the extent ref tree.
** Checking the fsroot tree.
** Checking volume.
** Checking the APFS volume superblock.
** The volume Macintosh SSD was formatted by diskmanagementd (1412.141.1) and last modified by apfs_kext (1412.141.2).
** Checking the object map.
** Checking the snapshot metadata tree.
** Checking the snapshot metadata.
** Checking snapshot 1 of 1 (com.apple.TimeMachine.2021-08-16-163638.local)
** Checking the extent ref tree.
** Checking the fsroot tree.
** Checking volume.
** Checking the APFS volume superblock.
** The volume Preboot was formatted by diskmanagementd (1412.141.1) and last modified by apfs_kext (1412.141.2).
** Checking the object map.
** Checking the snapshot metadata tree.
** Checking the snapshot metadata.
** Checking the extent ref tree.
** Checking the fsroot tree.
** Checking volume.
** Checking the APFS volume superblock.
** The volume Recovery was formatted by diskmanagementd (1412.141.1) and last modified by apfs_kext (1412.141.2).
** Checking the object map.
** Checking the snapshot metadata tree.
** Checking the snapshot metadata.
** Checking the extent ref tree.
** Checking the fsroot tree.
** Checking volume.
** Checking the APFS volume superblock.
** The volume VM was formatted by diskmanagementd (1412.141.1) and last modified by apfs_kext (1412.141.2).
** Checking the object map.
** Checking the snapshot metadata tree.
** Checking the snapshot metadata.
** Checking the extent ref tree.
** Checking the fsroot tree.
** Verifying allocated space.
** The volume /dev/rdisk1 appears to be OK.
iMac 27″, macOS 10.14