zlacker

While these are two common standards, you can easily implement DoH almost anyway you want if you are building a service or device. Its just replying to a request for a hostname record over HTTPS fundamentally - it can be as simple as an extra REST API you run. The number of "protocols" here is effectively limitless. I cant stress enough how simple it can be - check the specs you linked, the example HTTP request/response for the DNS over HTTP3 example is really basic - you could build your own in less than an hour if you really wanted and understand how traditional DNS works.

There is no such thing as right or wrong way to do DoH so long as the DNS messages are passing over HTTPS - the standards are largely to help make it easier to deploy and avoid common pitfalls of course (simpler to integrate to browsers and other software "for free" if the message response body format is standardised), but devices, apps and even javascript in the browser are free to solve this anyway they want, with whatever kind of message payload they can dream up.

DoH is just an HTTP request over SSL in most implementations, nothing more, with the record usually in the payload body in a JSON message or similar.