IPv6 disabled on LG /Network settings
IPv6 disabled in Server settings
Secure connections - Preferred
Plex app Settings add your manual server settings 192.168.68.111, port 32400
Plex app settings/ Advanced / allow insecure connections - on Local network also Insecure connections preferred on Local network.
Server settings / Network, add the following to List of addresses and networks allowed. 192.168.68.0/24
Router create Static/Reserved LAN IP’s for the Server and TV, in your case 192.168.68.111 and 192.168.68.108
I would also not use your ISP DNS on TV, use a public DNS like 1.1.1.1 or 8.8.8.8. You could also do the same on your computer.