Plex already has a search for duplicates in Movies (not TV which I find odd), but perhaps a better option is a suggested delete category. Some people’s media libraries get quite full, and a suggested delete category could be useful. This could be based on all users having watched a movie or show to completion, the movie not being in any users playlists, or a show or movie not being watched by any users over an extremely long period.
Like Duplicate file searches it gives the admin the option to delete, so they can still make the call that show/movie X is something they or someone they know may want to watch again.
