If you need an internet connection for some reason, run a network-wide DNS filtering solution like Pi-Hole or AdGuard Home, and make sure to set it as the default DNS server in your router
LG TV's serve ads in notifications via the same domain that distributes new firmware. I got so sick of it that I blocked my TV from being able to reach the internet but it's still on the network so I can still use wake on LAN to turn it on/off.