I'm using a seedbox and I can access it from anywhere, just fine. I'll be honest, I'm not sure about the implementation details, but I'm pretty sure it's done via a reverse proxy like so: https://jellyfin.org/docs/general/networking/caddy/
Wow. No idea this existed. I was about to set up a TV tuner with my Plex and pay $4.99 for the ability to broadcast live TV over Plex but see that JellyFin has this feature for free.
I would like a more logical arrangement of settings, remote setting of user resolutions (eg, please try native!).