Firefox adds NextDNS alongside Cloudflare for DNS-over-HTTPS (DoH)

Why is DOH only used for resolvers. What about authoritative servers. Caches are not authoritative soures of DNS data.

Nameservers for registries and registrars do not offer DOH. DNS over HTTPS is only used for "recursive DNS".

DNSCrypt has the same issue. It is used for resolvers only. It is possible to offer DNSCrypt from authoritative servers with dnscrypt-wrapper, but AFAIK no one does.