Doesn’t work for YouTube ads – they no longer load ads via DNS and instead embed them directly into the video feed. Ublock origin via the browser is the best way to block them. If you wish to use a client app, best bet is to sideload a 3rd party app like like SmartTubeNext for Android TV or YTLitePlus for iOS.

AdGuard blocks at the client level, so it works (so far) as far as I tested in the last couple of weeks (with a non-premium account).

Disclaimer: YouTube is still very affordable in India, our family subscribe to the YouTube Premium.