bootcamp assistant not formatting usb

Thanks, Loner. I appreciate your help. I'll try a smaller flash drive tomorrow and post progress.

Regarding the fusion, I do not know, I had a repair shop do it. If it helps, it lists the two drives as separate ones, not two volumes under the same one if that makes sense. I remember the Fusion before was listed as a disk with two volumes, one as the 3tb HDD and one as the 128gb SSD. Now in disk utility it lists the Samsung 2tb SSD as a separate disk from another disk titled "Unknown" and its listed as flash storage. Hope that makes sense and amswers the question.

Thanks, Loner. Here's the terminal output:

/dev/disk0 (internal, physical):

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      GUID_partition_scheme                        *121.3 GB   disk0

   1:                        EFI EFI                     209.7 MB   disk0s1

   2:                  Apple_HFS Untitled                121.0 GB   disk0s2

/dev/disk1 (internal, physical):

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      GUID_partition_scheme                        *2.0 TB     disk1

   1:                        EFI EFI                     209.7 MB   disk1s1

   2:                 Apple_APFS Container disk2         2.0 TB     disk1s2

/dev/disk2 (synthesized):

   #:                       TYPE NAME                    SIZE       IDENTIFIER

   0:      APFS Container Scheme -                      +2.0 TB     disk2

                                 Physical Store disk1s2

   1:                APFS Volume Macintosh HD - Data     12.9 GB    disk2s1

   2:                APFS Volume Preboot                 82.3 MB    disk2s2

   3:                APFS Volume Recovery                529.0 MB   disk2s3

   4:                APFS Volume VM                      2.1 GB     disk2s4

   5:                APFS Volume Macintosh HD            11.2 GB    disk2s5

Thank you so much for this clarity, Loner. I do not have a Time Machine backup as I did a factory reset before getting the new hard drive installed.

To be honest, having Windows 10 on my Mac is not crucial and I'd rather not rebuild or reconfigure my hard drive set up. Now that I know that it's because of the hard drive (Samsung) that BC and Windows doesn't work well with, then in my specific position it is not worth the trouble. I will just return Windows 10.

Thank you so much for your help and prompt responses. It really means a lot. I will mark the issue as solved.

Thanks, Loner. I do have a few externals and usually make clones of the entire disk before doing any software updates, plus have externals to back up individual files. Thankfully, I didn't lose any crucial data before doing the hard drive swap.

I will also consider using Time Machine from here on ou as a fresh start. Thanks for the suggestion!

I will add I also have the 128GB SSD from the old Fusion drive attached as secondary flash storage... if that could be an additional resource at all.