Boot Camp Assistant stuck halfway while partitioning disk

Hello together,

for the last day and a half, I've been trying to install a Windows partition on my 2019 iMac 27" using Boot Camp Assistant, but it's always stuck while partitioning the disk.

Things I have tried:

• Updating macOS
• Restarting in Safe Mode
• Using Disk Utility to run First Aid and remove failed partitions
• Creating a "test" partition using Disk Utility, it worked perfectly fine
• As a last resort, I have now resetted the iMac to factory setting, to no help

This is the output of diskutil list:

/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS                         3.1 KB     disk0s2
   3:                 Apple_APFS Container disk2         1000.0 GB  disk0s3

/dev/disk1 (internal):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                         28.0 GB    disk1
   1:                        EFI EFI                     314.6 MB   disk1s1
   2:                 Apple_APFS Container disk2         27.7 GB    disk1s2

/dev/disk2 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +1.0 TB     disk2
                                 Physical Stores disk1s2, disk0s3
   1:                APFS Volume Macintosh HD            20.3 GB    disk2s1
   2:                APFS Volume Preboot                 45.0 MB    disk2s2
   3:                APFS Volume Recovery                509.7 MB   disk2s3
   4:                APFS Volume VM                      2.1 GB     disk2s4

The 3KB disk0s2 partition is displayed in Disk Utility as well and was generated during my errands (it wasn't there when I started). I can't seem to erase it.

Thanks for your help!