Plex cannot see that this 1 video exists

Plex Documentation → Your Media
→ Naming & Organizing Your TV Show Files
→ Editing Libraries

You need to follow Plex naming requirements.

Plex Dance the entire show after renaming and reorganizing the episodes. This removes incorrect information from the Plex database.

/TV Shows  <-- TV Library points here.  Name unimportant
.../A Dog's World with Tony Armstrong (2022) <-- show_name (year)
....../Season 01 <-- "Season" in English.  Two digits for number.
........./A Dog's World with Tony Armstrong (2022) s01e01 Friendship.ext  <-- ext = mkv/mp4/etc

Also, it is a new TV show not yet entered at TVDB.com. You will need to tell either the library or the show to use TMDB for episode information.

At the library level:

  1. Edit the Library (See support doc above)
  2. Choose Advanced
  3. Choose The Movie Database for Episode Ordering
  4. Refresh the metadata for the library.

At the show level:

  1. Edit the show (click on the pencil icon)
  2. Choose Advanced
  3. Choose The Movie Database (Aired) for Episode Ordering
  4. Refresh the metadata for the show