I am currently using one that is prevented from connecting to the internet via firewall rules from my router and all media comes from a separate jellyfin server. Had to allow enough of an internet access to install the app but once that was done, everything going outside lan is blocked.

Also most tvs have usb ports so maybe either raw media or some third part dongle can service as well?

Also also, most tvs of this caliber have hdmi you can plug your computer to.