And of course if you watch YouTube on a PC browser with an ad-blocker, you will never see the ads. But most of our viewing is on the big TV using a Fire TV Cube. I'm not aware of any ad-blocker that runs on the Fire TV platform.
I wasn't aware that an ad-blocker would block YT ads BUT if you are looking for a blocker for your Fire TV, and don't mind doing a little computer work, you might look into pi-hole. It will block everything coming into your computer.