FWIW, I have an LG LED smart TV (2xHDMI, 1xDVB-S2, WiFi, NIC, etc) and it's only been connected to my network once, for a post-purchase firmware update through my AdGuard Home. WiFi and Ethernet is disabled, and I use it with my Nvidia ShieldTV (Plex*, Netflix, ChromeCast, etc).

I won't let it go online as I expect it already phones home if you let it, and don't imagine LG will be able to resist ad injection into content, like Samsung and others do. So it's an excellent quality dumb TV, which meets my needs perfectly.

*Plex Media Server runs on my NAS. The Shield and my mobile devices are Plex clients.