Looks like a good alternative if you can't get root. It uses VPN to blackhole requests.
If you have root, I'd use AdAway[0] which changes the hosts file directly.
Another great alternative is Blockada[1], it does the same as DNS66 and Adaway but in my experience does it felt much more reliable. It is available on f-droid[2]
[1]https://blokada.org/index.html
[2]https://f-droid.org/en/packages/org.blokada.alarm/