a) It's not official, or even recommended at https://jellyfin.org/downloads/clients

b) I would never use an app that used VLC for playback.

It’s there. jellyfin.org/downloads/clients/all/

And it’s in their repo.

It seems to be status “official beta” and closing in on a new release with a considerable amount of rework done.

I’m running a local build deployed to my appletv and it’s working fine.