For me personally, integration with something similar to the plex_debrid script.
I love how easy it is to add something my plex watchlist and have the plex_debrid script fetch it, add it to my debrid account, update the network mount, and automatically refresh my plex library in a matter of 2 minutes tops.
If jellyfin had a similar integration/feature I would switch over in a heartbeat.
For me personally, integration with something similar to the plex_debrid script. I love how easy it is to add something my plex watchlist and have the plex_debrid script fetch it, add it to my debrid account, update the network mount, and automatically refresh my plex library in a matter of 2 minutes tops.
If jellyfin had a similar integration/feature I would switch over in a heartbeat.