Folder in collection

[theguymadmax]

So, is your collections directory set up in Jellyfin as a mixed library? I tried to follow your structure, and the setup below works. It allows the TV series to be added as a subfolder within the hidden collections library and when added to a collection.

Hidden collections directory
│
└───National Treasure
    │
    ├───National Treasure (2004)
    │  └───National Treasure (2004).mkv
    │
    ├───National Treasure: Book of Secrets (2007)
    │  └───National Treasure: Book of Secrets (2007).mkv
    │
    └───National Treasure: Edge of History (2022) [tmdbid-137437]
        └───Season 01
            ├───National Treasure: Edge of History (2022) [tmdbid-137437] S01E01.mkv
            └───National Treasure: Edge of History (2022) [tmdbid-137437] S01E02.mkv