Plex is very picky with TV shows.
See Plex Media Preparation Guidelines, specifically, Naming ‘Series’ & ‘Season’ Based TV Shows.
Regarding what you have for The Twilight Zone, you’ll need to dump all the download naming and re-name things a bit to meet Plex’s requirements. After renaming things, perform the Plex Dance to help Plex pick up the new names/structures.
Try:
/The Twilight Zone (2019)
/Season 01 <-- two digits
/The Twilight Zone (2019) - s01e01.mkv <-- note spaces and dashes, not periods
/The Twilight Zone (2019) - s01e02 - Nightmare at 30,000 Feet.mkv <-- episode name optional
Also, look at the metadata inside the files and delete any “garbage” in the names of the segment and audio/video/etc tracks (the files sometime have the download file name, not the episode name, audio format, etc). MKVToolNix (header editor) and MediaInfo are good, free tools that can help view/modify metadata.