I'm not sure why you say this....I see no ads in Google chrome, on either desktop nor mobile.
As far as I am aware, Google do not hardcode DNS servers into their software, but they perhaps do hardcode DNS servers into hardware, such as the Chromecast and Google Home devices
The basic summary of this thread is in order to get Pi-Hole functioning on an android device, I had to disable IPV6...at least for my ISP anyway.
confirmed by a fellow Sky (UK ISP provider) here in another thread