Blocking ads at the DNS level is very limited. All that has to happen to bypass it is the site you're visiting serves the ad data directly or really just from a

Blocking ads at the DNS level is very limited. All that has to happen to bypass it is the site you're visiting serves the ad data directly or really just from any domain that also serves up info you don't want to block. It also can't do anything to counter anti-adblock mechanisms or to clean up the layout which might have space already reserved for the ads. Using a MITM to alter the responses is an option, but you're likely to run into issues with sofware and devices not being able to handle a custom CA.