“Anything else anywhere else”

Clarify - do you mean remote access? Are you using your phone for local access (eg localhost:8096 or 192.168.0.1:8096 or some kind of mDNS like arch.local:8096)? None of that will work outside of your home without additional configuration nor should you just openly expose it to the greater internet without doing much more research. Short version though - easy mode: tailscale or wireguard, harder version headscale but can be fully self hosted.

If this isn’t a remote access issue and it’s just some devices aren’t working locally (eg your phone and browser can connect but tv can’t) I would bet it’s a networking issue with firewall/router. What do logs say? This is one that can be trickier because logs on jellyfin side won’t necessarily have any useful info (they might if client is trying and failing to connect, worth a look) and logs on the other side might be a nightmare or even impossible to access (eg a smart tv and you don’t have a developer account for apple/android/webos)