I have no cable and my TV isn't hooked to anything except a Chromecast so I can stream to it. Can TVs send stuff out over Chromecast? I feel like it's no but?
HDMI does have a feature called Ethernet over HDMI that in theory could allow that.
Thing is though it’s literally never been implemented in anything. It died because cheap WiFi became common.
For it to work you’d need both the TV and Chromecast and HDMI cable all to support it. It’s not uncommon on cables and a surprising amount of them include it in features list (probably to trick low info people).
But I believe that’s a hardware design thing so not something even a software update could enable. It costs extra money and they’re already paying for a WiFi chip so why bother?
I tried Jellyfin and the performance for me was sooo much worse than Plex on the same system. Videos took forever to play. Also Plex is way easier for me to share with family than Jellyfin.
You can check to see if you can enable hardware transcoding. I find the delay is usually transcoding building up a buffer and if you have a good GPU/APU in your server it's often a lot quicker.
Pretty sure on jellyfin by default that is off. Mainly because you need to install some packages to get the devices available under linux usually.
I'm not seeing any replies that are super helpful for your question - so here's what I do: throw a Linux desktop on a Raspberry Pi, or NUC and use the TV like monitor. Get a wireless keyboard/mouse combo and watch Plex through the appimage or just Firefox. Bonus, now any website that does video can be viewed on your big screen tv without dealing with any casting apps.