Another option if you have good control over your router is to put the TV and other smart devices on a special subnet or vlan and only occasionally give it internet access for updates, etc. Maybe there's a good DNS-based ad blocker you could run on its vlan and nuke all of its ad and spy traffic too.

This actually seems like a good market opportunity for yet another home device, a router with aggressive spyware and ad mitigation that's made to explicitly connect all your smart gadgets and untrusted devices that phone home.