Best Way to combine folders but eliminate duplicates

A while back I had a problem with a database - I’m sure I caused this myself but at the end of the day the new database had a long list of missing files - I saved the list and went on. I have an old version of the same database which contains the missing files, which I have renamed by adding a 2 to the end, put into my database folder, and opened in DevonThink. I am not 100% confident in the missing files list, so what I’d like to do is add the files and folders from the old database to the new one and then eliminate duplicates. What is the best way to do this? The database has over 2000 items so I would rather not do it completely manually (although I will if I have to!)

Thanks!

My goto tool is Applescript

Another possibility might be to…

  1. Import the files from the backup to the database
  2. Search for name:!>2 item:duplicated kind:any via the toolbar to find all documents that are duplicates but don’t have the suffix 2

All or most of the search results are probably the missing files.