It is just in name only and Plex (mostly) uses TMDB.
I had to add some of my shows to TMDB that were on TVDB but no longer worked when I got the notification to "upgrade" library.
Would it be possible to use TheMovieDB, since already implemented for movies, for tv show matches as an option, or does that mess up the aspect ratio?
The reason - I have some old episodes of Digimon Fusion. Wikipedia says it's 3 seasons. TheMovieDB says it's 3 seasons. TheTVDB says it's 3 seasons. Gracenote says it's....7. So it's a mess. I realize I'm ad edge case, but I'm guessing some of this older DVD media might run into the same problem.
I'm with you, especially with non-USA origin content. Gracenote did some updates recently and a bunch of stuff I've had problems with forever got updates (or were added for the first time), but still plenty of issues. Metadata is my nemesis.