CarbonCopyCloner and SuperDuper both create perfectly acceptable external bootable clones of Big Sur and Monterey using Apple's own cloning utility and it is possible to "refresh" the data volume on one of those clones using CCC and probably SD as well. But there is a significant caveat that is true for any bootable external drive in either macOS 11 or 12
whether it was created by Apple's cloning utility or by the macOS installer. There is a tiny partition/volume (Disk0s1) on the internal SDD/HDD that is required
in order to initiate the boot process from any drive whether it be internal or external. (I cannot verify this, but I also believe that volume MUST be on the internal drive in order to work.) So external drives will not and cannot boot without this partition on the internal drive and therefore are not true clones in the sense of clones in macOS 10.x.
The Disk0s1 partition is NOT created by the installer, it is encrypted and, at least theoretically, cannot be copied. The only way to create that partition is to connect the target Mac to another Mac running Apple Configurator 2
and run the appropriate install package from there. I have tried that and it isn't as easy as it sounds. (On an M1 MBP it takes three or four hands and a timer to initiate the connection 😳)
If SyncFoldersPro has figured a way around that it would indicate a vulnerability in the system and I would be reasonably certain Apple would take immediate steps to patch that vulnerability.ADDENDUM:
After viewing the web site and watching the videos, without investing $$ in the Pro+ version of SyncFoldersPro I don't see that SyncFoldersPro offers anything that is not available in CarbonCopyCloner or SD other than some catchy promotional videos and a different, perhaps glitzier, GUI. Because of the same issues Mike Bombich and David Nanian ran into, I strongly suspect SFP is using Apple's cloning tool just like the competition and is subject to the same limitations. That is an observation not
Speaking of Apple's cloning tool Mike Bombich refers to it as Apple's "legacy
" cloning tool which leads me to wonder if Apple officially considers it "legacy" which means available but no longer supported. If that is the case clones per. se.
could become a passing memory in a future macOS upgrade or when Apple drops Rosetta?