[Request] Set DNS Server choice by priority/tiering (primary, secondary, tertiary... server)

So, I actually like the older Simple DNSCrypt method of setting a primary and secondary server. I really prefer to use AdGuard DNS when I can, and when I can't I'd switch to Cisco OpenDNS. I'd like to be able to do that, I'd like to assign priorities to use certain DNS server and only switch when that server is having an issue (down or slowdown).

Is it possible to have that?

PS: When is Cloudflare DNS coming to the DNS server list?