PiHole, Adguard Home and the like can’t block ads on smart TVs? Or is it something like the TV refusing to start if it contacts the ad server and doesn’t get a response?
PiHole blocks by preventing certain domains from loading (the ones you specify on your blocklist). It’s not examining any content. It simply sees a request for say examplespamdomain.com and blocks it when something on your network requests it. Youtube serves ads and videos from the same domain, so this approach doesn’t work.