Mandatory reading: https://support.plex.tv/articles/naming-and-organizing-your-movie-media-files/
Put every movie in its own subfolder.
Don’t use ‘Collection’ subfolders. (or if you do, put every movie inside the collection folder again into its own, individual subfolder)
Name the movie files exactly after the official recommendation
Official Movie Title (year) - [anything else like codecs etc]
If there are .nfo
files in the same folder, make sure they contain the correct IMDb ID for the movie.
Use the Plex Dance to clear out persistent mismatches from the Plex DB.