I've got a Samsung smart TV I purchased a couple of years ago. I've never seen a single ad on it (the drawback is that the TV's app store doesn't work either as it belongs to a domain also used for ads).
When I tried to disable the PiHole for a couple of minutes, I couldn't recognize my TV anymore. Ads in the menu, ads popping up in the corners of the TV, ads everywhere.
It's no coincidence I guess that my smart TV is the main offender when it comes to requests to blocked domains on my PiHole.
Just get a PiHole, and, unless the TV manufacturer refuses to pick the DNS server used in your network, or they've found ways to inject ads without hosting them on blocked domains, you won't get a single second of harassment.