VTPKs tend to be unforgiving if you try to modify them
There is a tool - Extract package - that will extract the tiles and other files.
There is no way I see of reversing the process. Simply zipping it back up (uncompressed) will not do, because it doesn't want the tiles in exploded format
I found this link for packing files in your compactV2.
But is it meant to work on Vector tiles?
The root.json of a vtpk will say:
It mentions "compactV2" which pointed me to this code.
But some other things cause me to doubt.
1. The set of files becomes 50 times bigger. Not very compact.
2. ArcGIS Pro and ArcGISOnline cannot find any of the tiles in the new vtpk.
I may have good reasons to use scripts to repackage tiles in vtpks. The vtpks often take days to weeks to generate and I might want to avoid redoing them just to get smaller areas.