Skimmed first and last pages, lots of feather fluffling here.
Keeping things simple, ALL that need doing is:
-unpack compressed archive
-delete any offending 'extra' files
-use TOUCH to bulk-blast your desired timestamp into all pertinent EXIF slots in all the files/folders (one step!)
-jam files back into fresh archive
Honestly, all this jazz about borking your system time is overkill, and can lead to unforseen trouble with not a few various background processes. You *really* don't want to do that in cases where say BITS is trying to marshal one of those Windows Update enemas... things can break and BITS is a bitch to fix.
Also, Powershell is one of those tools that can really do horrendous damage with a minimum of user-error. But if you're proficient enough to be comfortable using it safely, you're also probably experienced enough to realize you're cutting daisies with a chainsaw.
Really, the process is simpler that what I've seen proposed... :p
Also... wasn't it Abad that predicted this years ago? I seem to remember a convo about hoping the model mills don't attempt to get smart.
Anyway, TOUCH (for windows):
https://sourceforge.net/projects/touchforwindows/
I've used Touch for many many years, it's any hacker's must-have for the toolbox. For exactly this scenario.