Where is Money Heist season 5?
Due to issues caused by netflix buying the show, and metadata sources not agreeing on how to organize this show, you cannot assume it is organized correctly within plex.
Elysium holds 5 seasons of Money Heist, organized as season 1 through 5. On your appbox, you might only see 4 seasons, or 5 seasons with season 5 only having 2 episodes - The season 5 episodes are most likely merged into season 3, theres nothing you can do about it.
Episode 1 and 2 might show in season 5, while 3 through 5 might be merged into season 3. In this case, click season 5 and play the 2 first episodes, to watch the remaining episodes, go into season 3, click episode 3,4,5 and click "play version", play the 2nd file to play season 5.
In the event all season 5 episodes are merged in season 3, follow the same procedure above, but for episode 1 and 2 as well