This is a secure dns and adblocker that has evolved into a great privacy app. Yesterday i noticed it has added support for Wireguard and TOR as well as proxy. The app comes with a customizable firewall. It means you can have secure dns combined with vpn/proxy and firewall in one app.
P.S: I’m not the developer.
You can use max.rethinkdns.com as Android’s default dns.