To actually answer your question without snark, it’s still miles behind. I give the competition a shot once every year or two to see what’s up. It’s never even close for someone that prioritises the things that I prioritise. Every Plex competitor I’ve used makes me feel like I’m using a Linux media player in 2008. Some people get off to that. I don’t.
For some reason the best clients are on Apple devices only, that Infuse and Swiftfin. mpv shim is ok too. That’s my only gripe since I barely touch the actual Jellyfin server interface, it just works. If I had Plex I would also use Infuse too so there’s really no difference except that one is open source, doesn’t phone home, and doesn’t require a monthly subscription.