I have a TCL QM8, which until recently I was using for its full smart-TV capabilities, and always feeling rather icky about all of the stuff it was sending. I would keep getting notifications about the microphone being turned on even when I had explicitly disabled it at every level.

I eventually got an NVIDIA Shield Pro, for which I:

1) Blew away the default launcher and installed Projectivity

2) adb disabled nearly all of the background Nvidia/Google services, following a guide

3) Removed all of the preinstalled streaming apps and added back the ones I use, opting for more privacy-respecting alternatives like Smarttube over YouTube standard.

Finally, I then factory reset my TCL TV and put its Google TV into "Basic" mode, which makes it a dumb TV for all intents and purposes. The TV itself is not allowed to connect to the internet anymore for any reason--everything goes through the set-top box.

The skeezy thing is the TV still tries very hard to get you to enable regular mode. Like if you try to launch ANY app of ANY kind, it will throw some pop-up about needing to connect to the internet to do so, and then flashing some fine print about how this will revert the TV to normal Google TV/Android TV mode. I had a guest in my house using the TV while I was in another room and suddenly asking me for my WiFi password, and when I went to see what was up, saw that they were halfway through opening the floodgates again before I stopped them.