Sorry for the confusion I get it now.This has nothing to do with you router!
Your ad traffic will be filtered through AdGuards DNS servers on your iOS device only!
Try AdGuards custom DNS Servers and judge for your self!
Update: When reached for clarification, Apple said “This is not a new guideline. We have never allowed apps on the App Store that are designed to interfere with the performance or capabilities of other apps.” It also said it would remove other apps that offer features that block advertising in third-party apps if they “may have snuck on to the App Store.” Apple added, “We have always supported advertising as one of the many ways that developers can make money with apps.”