AFAICT, keeping the TV offline (i.e. not connected to any wifi) and plugging in a laptop/Chromecast/etc. via HDMI would eliminate both sides of the problem. You can still use streaming services on the laptop, but the TV would be unable to phone home.
There’s always the yar har option as well, which is also effectively implemented with a laptop.
Yeah, someone should definitely do that. I think this is written from the perspective of a security researcher communicating with others in the security world about a discovery they made, so it’s a) dense to read, and b) not thorough as a consumer guide.
Hopefully someone follows up with a resource like you describe.