What I would do it set your TV library to Plex TV Series if not already but change the ordering to be THETVDB like my first screens shot for library. then do the plex dance on that show folder/files. ( make sure you do all the steps)
I’m not sure why it is not coming up in search though. it is really odd. It matched correctly for me first try without having to fix match. Watch.plex.tv does display results mostly matching TheMovieDB for most things. I suspect it not being on TheMovieDB at all is what is causing the problem on our end but I’ll let our metadata team know.
