Just thought it’s worth mentioning that with the introduction of Smart Collections (Plex Web 4.56.3, PMS 1.22.3) you can now achieve the desired behavior.
I deleted my “classic” MCU collection and replaced it with a smart collection. I used the Match any of the following group (new Advanced Filter feature) and included the collections / individual movie titles as filter criteria (e.g. Collection Is Iron Man, Title Is Black Panther…).
Smart collections don’t interfere with how their items are displayed. They’re basically just a grouping that will be displayed if collections are enabled for that library.
With that, Plex will display my regular collections (Iron Man, Thor, Guardians of the Galaxy…) as well as the individual movies (Doctor Strange, Black Panther… next to the smart collection MCU.
