Why would you use Google/OpenDNS/whatever when you can use dnscrypt [1]?
The list of resolvers they have there it's not exactly obvious why I should trust any of those more? (and OpenDNS is on that list) https://dnscrypt.org/dnscrypt-resolvers.html
Here's the Turris documentation on how it handles DNS: https://www.turris.cz/doc/en/howto/dns