For starters, S1, S2, etc are not the proper naming conventions, they need to be:
Season 01
Season 02
etc
Review this support article: https://support.plex.tv/articles/naming-and-organizing-your-tv-show-files/
Fix up your folder and file names and then do the The Plex Dance ™
Similarly for your movies folders and files, in particular for movies (and tv shows for that matter) that have multiple release years (e.g. Dumbo 1941 versus Dumber 2019) you will need to include the year in your naming.
https://support.plex.tv/articles/200381043-multi-version-movies/
