The Finder doesn’t create or mount APFS snapshots. And while I haven’t tested it, I fully expect Time Machine to still enforce Unix file permissions. You really need to be using the command line to do what you’re describing.
I haven’t tested the Finder case though. Nevertheless there is the `tell ‘Finder’ ... do shell script ... end tell` construct that _may_ be able to get the Finder to launch an arbitrary subprocess (and may inherit full disk access) just like how Terminal would.
However I’ve tested mounting a local snapshot using the Terminal having full disk access and found out that it is possible to mount a local snapshot and make the mounted copy ignore Unix file permissions.
