By the way, the issue is not that the media is not tagged correctly. Jellyfin detects the media just fine, and identifies it correctly as the correct movie and TV show and whatnot. That isn't the issue. The issue is only that of duplicate detection. So if Jellyfin can detect the shows and movies correctly, it should be a simple problem to solve that it just looks up those IDs in the database of content, and merges them.

The big problem is UI, and implementing a nice solution for that. Plex has done that part, but Jellyfin has not, without a plugin. That's it, really.