If you watch the video, (oh boy was it long but informative) it likely is still spying on you rampantly and using neighbors as hotspot points to send the data.

Unlike smartphones, they are plugged in so they can just run speech to text (and the TVs that the op had could hear 20m away in other rooms with the mic array) forever. If you sell the TV or something and it ever connects to the internet again, it will likely dump all of that plaintext data corresponding to your physical location.

I picked up a second hand circa 2011 nearly smart TV. It's sony 65" 1080x1920 plenty of inputs. Was a high end device of it's day.

Cost me $100.

Unfortunately we will run out of old devices like this at some point.