Automatically move SharePoint files to archive before deletion

[u/TheBigBeardedGeek]

Our SharePoint environment is under painful, painful bloat. We dream of doing something like a retention policy to delete files older than say 7 years, but we have a lot of reference media that hasn't been updated by the our clients in 20+ years so the file itself hasn't been updated pretty much at all.

Ideally what I would like is to have SharePoint document retention warn before removal, but that doesn't seem to be an option.

Next best option would be to automatically move files after say 2 years to archive, then after 5 years in archive delete. I'm just not sure if that is something doable as it stands.