I've got about a dozen (yeah, I know, not a lot) anime series on my Jellyfin, and also prefer subs in nearly all cases. I've had a problem with them. But, if someone's got something that's already working, they should probably just stick with that.
They have a plugin for JellyFin, ShokoFin. And I believe they do have a integration with Plex.
This replaced my previous setup and it works amazing with my Kodi.