One thing that surprised me when digging into Apple Photos is how much state isn’t represented by just files-on-disk. Albums, Live Photos (paired assets), bursts, slo-mo, edits, and even “simple” things like adjusted capture dates are all tracked separately, and most export/backup tools end up flattening or partially reconstructing that on restore.
The approach I took was to treat Photos as the source of truth and verify restored items against it, rather than assuming filesystem metadata is enough. As far as I know, this is the only tool that restores albums and correctly round-trips all Photos item types while preserving location data, creation dates, and modification dates when restoring back into Photos.
Project page is here if it’s useful: https://photosbackup.app/
Happy to explain details if anyone’s curious — there are a lot of sharp edges in Photos once you go beyond “export originals”.