What values to set in Static IP Settings of Wi-Fi when changing DNS?
You should use OpenDNS Family shield which blocks porn and malicious websites.

Dns1: 208.67.222.123
Dns2: 208.67.220.123


If your ISP blocks other DNS's, try a secure connection (use Port 443):

Dns1: 208.67.222.123:443
Dns2: 208.67.220.123:443


If you're phone has root access I recommend using a paid app called OverrideDNS which encrypts your DNS queries like DNSCrypt and makes you forget about all DNS issues that you might have, it also works on cellular data.