What I did was just buy the tv I wanted for the hardware and block it from internet access by Mac address, then plugged it into the network with eth. I then put dns blocks on every request it made (I log things before blocking them, and did this on the scenario a kill switch gets messed up or something) and installed the media software from there. Smart tv made private.
Just gave it a try… Doesn’t appear to work for browser default search settings? I do a search and see results for about 2 seconds before it then shows their search page. I used
https://www.qwant.com?q=%s
for the query. Liked the search results I tested it with but not being able to use the search bar for quick searches is a deal breaker for me :(