I believe genexx may be onto something in reply 28 above.
A friend (who had just bought a new Studio) went through a similar experience while trying to create a cloned backup using SuperDuper.
He was using a LaCie portable SSD that had worked on his previous 2012 Mini.
But... SD couldn't create a cloned backup on it.
Kept throwing errors similar to the one the OP posted above.
Something that seemed odd to me was when trying to erase the LaCie SSD using disk utility, DU didn't offer "APFS, GUID partition format" in the erase menu.
My friend was eventually able to format it to HFS+ and then "convert" it with disk utility, but the subsequent attempt at a cloned backup STILL wouldn't work.
I advised my friend to try a DIFFERENT DRIVE.
He bought a Samsung t7 "Shield", and the format and cloned backup (again using SD) went through without any further problems.
My guess is that there was something in the LaCie drive -- controller chip, circuits -- something -- that just wouldn't work right with either the Studio's hardware or the more recent version of the Mac OS (Monterey).
Changing the drive SOLVED the problem.
So, msg to the OP of this thread:
Do you have ANOTHER DRIVE you could try?