/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.
I am familiar with the plex dance and the naming convention. It’s not the matching either. Titles which do match(manually or automatically) don’t show any metadata. And this is recent because I didn’t have an issue just a week ago.