Most of it comes down to the user. You need to be precise about naming and sorting media with all of these media libraries. With non-standard media - like fan edits, combined episodes and the likes - my usual shortcut is to place it in bonus feature of regular media.

I've been running plex since plex was a thing. Switched to jellyfin as soon as I heard about it, because plex kept getting worse. The advertisements and integrations to other services are shoved down your throat in plex, I just need a media library.

But facts are facts, plex is far superior when it comes to tagging, matching, and generally working with metadata. There isn't even a filter in jellyfin for unmatched media, nor a duplicates filter. In plex I can very quickly narrow down issues by using those filters.

Neither have native metadata export, but there are associated extensions for both, and the one in plex grabs 70 data points. Jellyfin does 16 and it has to lock up my browser for 5 minutes to think about exporting that csv.

I use jellyfin all day for watching, but I still spin up a plex install when I make major additions to my library because it's way, way superior.

You sound like a weird little fanboy.