Also beware as most ads in your phone apps come from ad intermediaries that are either dynamic or constantly change.
Pi-Hole is a cool project but please take in consideration those two when using it. We are far from the 90's in ad-tech.
Surely Youtube being the size it is has a few Github issues against it saying 'I can't load images because I block the ads'?
I guess what I'm saying is, what is the negative impact of your first point? That some content you want won't come through because the content you don't comes from the same domain?
This is because Youtube serves content and ads from the same domain, so you can't domain-block ad content without blocking all content.