1.1.1.1 is cloudflare not opendns. Also you need to use something like unbound as recursive DNS because most of people using pi hole or adguard home they are forwarded DNS and still need upstream. But I agree with you, I run unbound+ Adguard home and don't need anything. I put 9.9.9.9 as fallback however because I don't have replication of the setup yet.
In the past, for many decades, dnscache was an excellent recursive resolver and cache. Unfortunately, it has become obsolete because nowadays many DNS queries return replies so big that they must be obtained over TCP, so an UDP-only tool is no longer good enough.
