Structure and naming.
Wrong:
H:\Movies\English\2019\Avengers.Endgame.2019.1080p.BrRip.MkvCage.FilmZone.mkv
Right:
/A Movie Library <--- Library points here. Name not important.
/Avengers Endgame (2019)
/Avengers Engame (2019).mkv
or
/Avengers Endgame (2019) [all that other stuff].mkv
Plex does not like subfolders (except to hold the movie itself and any extras). Using your folder structure, the library would point to ...\2019. You should clean up the file name as well. All the extra stuff makes it difficult for Plex to match the movie. If you want to keep it, put it in square brackets, as Plex ignores info inside such brackets. This post explains why the extraneous information causes difficulties with matching.
Reference: Naming and Organizing Your Media
After renaming & restructuring, perform the Plex Dance to clear bad data from Plex’s database.
If you’ve many movies/shows to rename, consider FileBot. It has a pre-defined template for Plex.
