I had a lot of trouble jellyfin and anime until I started putting things into season folders, even if they only had one season. So if I had Ano Hana I’d put the episodes in a folder like this
Media Disk/Anime/Ano Hana/Season 1/episodes_here
If it’s a movie, then it goes into a folder with other movies.
Media Disk/Anime Movies/movies_here
Once I started doing that, Jellyfin automatically recognized most Anime.