Hi @chrisblankde,
Can you please tell me what metadata you are trying to update? If it is just the version, you can use the Repackage API. If it is something other than the version, in ProGet 2023, we added the ability to edit the upack metadata directly in ProGet. You can do that by navigating to the package version in your universal package feed and then click "Edit Package" in the upper right corner.
If neither of those options works for you, then what you suggested (download/extract/edit/repack/upload) would be the way to handle this.
Thanks,
Dan