I connected my TV to the internet to test some Wi-Fi streaming before, and I noticed after a few days the number of blocked queries my DNS had blocked. So, I kept it running for a few days. On average, it blocked more than 15k queries a day! And that’s in idle mode and/or turned off, so I wasn’t running any YouTube, Netflix, or similar.
If you're just looking at number of requests blocked, that can be highly deceiving. A lot of these "smart" TV OSs (and other embedded devices) will very rapidly spam the DNS server with no backoff when they don't get the expected response.
Some of these tvs also hardcode DNS IPs. If your router supports it -- check the outgoing traffic from the tv to the standard DNS ports.