Disable all internet functionality, set the time to the 1990s to prevent many timers from going off, attach the tv to another device that doesn’t have ads via your cable of choice. But why was your smart tv 1700? Did it have some special features?
Not disagreeing, but at some point this won't be enough. Assuming companies aren't already, "offline" devices will get shipped with the ability to utilize unsecured networks and/or other devices. Better hope any neighbors are privacy conscious too.*
I’ve been recommending physically snipping radios, but that can cause issues if you don’t understand what you’re doing. Any chance you know whether it’s possible to simply delete drivers and backups on modern smart tvs? Mine is ancient, so I have no clue what they’re doing to y’all, nowadays.
Personally, I don't have the energy to go to such lengths. My "good enough" has been using AdGaud Home as a network-wide DNS blocker and connect my smart TV to it. It's been great so far.
Plus, I get the bonus of seeing how much gets blocked.