It doesn't load quickly unless you avoid Plex servers, because authentication happens through them

I’ve never had this issue

As for the interface, the Plex interface is to the point. Jellyfin is missing a huge amount of additional information that both I and my users rely on. If you just want very simple information, fine. But both I in my users don’t. They expect a rich media experience that Plex delivers and jellyfin does not.

I guess it really comes down to which experience delivers what you’re looking for. Plex delivers what I’m looking for and what my users are looking for. Jellyfin just doesn’t. But I’m glad that you’re getting what you want. And that’s what makes it the better choice for you and what makes Plex the better choice for me and my users.