That is my problem. What can you trust anymore? Is there an appliance out there that can do the basics and not be a malware gateway?
Smart TVs replaced dumb TVs not out of consumer demand, but out of subsidy from commercial databrokers and streaming services. Despite adding $100 of hardware they were priced $100 cheaper.
You could give it a vpn to a public cloud provider so that even if they run residential proxies they still get a dirty vps IP.
Admittedly this doesn't stop the presumed screenshotting and microphone use and worse