It seems Plezy, a quite polished Plex client a number of people had been using instead of the official Plex apps (which are a bit of a mess now) has added Jellyfin support and a version for the AppleTV.

Added

• Jellyfin support
• Live TV DVR and recordings
• iOS external display playback
• tvOS support

Fixed

• ExoPlayer ASS subtitle delay
• iOS PiP subtitle issues
• Plex startup, home hub retries, and endpoint failover
• Sync rule removal/navigation
• Various focus issues

Improved

• Playback and player UI performance
• Discord Rich Presence posters
• iOS energy usage

https://github.com/edde746/plezy/releases/tag/2.0.0

At first glance testing out the desktop version while waiting for the Play Store and iOS App Store to be updated it seems to carry over very well into Jellyfin. It's also very easy now to switch between users without needing to log in over and over again.

It's also very handy to switch between Jellyfin and Plex or indeed display media from both types of media servers on a unified homescreen, making mixed setups that much easier.