“Will not connect to the internet” is probably too vague to troubleshoot. Isolate exactly what part is failing. Is the device receiving an IP address? Are you able to ping anything on the local network? Are you able to ping a remote IP address? If you aren’t receiving an IP address, is DHCP running? Can you statically set your IP and ping out? Is there another switchport you can try on the router?
Depending on how much storage you are needing for media, one possible option there (if nothing else until you can find a more cost effective solution) is to host the media remotely. You can use rclone to sync remotely to a local mount point and then point your Jellyfin library to that mount. pCloud is a popular choice for stuff like that.