Note that this is the JSON-specific format [3]. DNS over HTTPS itself uses the DNS wireformat [4], so you would have to build a parser for that if you want to integrate it into a web app.
That's a HTTP request no matter what data is being returned. Fact still stands that there is no JS API in browsers to make proper DNS requests (without HTTP).
DoH in its current implementation is just a tunnel using https to reach someone elses centralized servers that are using port 53 DNS. The root servers do not yet support DoH/DoT and I would be pleasantly surprised if they ever did.
Most of us are on the other end of the DNS hierarchy, and send queries to recursive resolvers, not root servers. Root server operators are conservative and there's much less of privacy consideration when traffic is mixed with others at a resolver.
