I tried one of the steps which was making the pihole machine the only dns server, also on clients and it seems to be working. The last thing i had not tried was the /etc/hosts method, which i will try as well.
But i picked up a strange thing, not sure whether it is a buug or what, but if i visit the Ookla speed test which has ads, the page will not hav any ad, but if you refresh the page and scroll down on it, the ads return.