I have added episode level external ids from tmdb to both imdb and tvdb. This may or may not help, certainly won’t make things worse 
While we wait for the plex metadata back-end to pickup these changes could you check the show level guids as they are reported in plex. Here is a link on how to do that if you are not familiar with the process → Show "Sunny (2024)" getting incorrect metadata and has multiple tmdb ids - #18 by dokuro.
