The problem I have with DNS over HTTPS is that it's something implemented in the browser, that ignores the DNS configuration of your PC and your local network.

The problem I have with DNS over HTTPS is that it's something implemented in the browser, that ignores the DNS configuration of your PC and your local network. That has some implication, for example you are unable to access local hosts on your network by their hostname (for example https://fileserver https://fileserver). Also you have a solution that works only on one program, while the rest of the system DNS requests remain unencrypted, that is bad. Browsers shouldn't implement DNS theirself, and should use operating system APIs to do all the DNS queries. That is how networks work, and doing that differently creates problems (imagine if every program has its implementation of DNS over HTTPS, you have to configure correctly the DNS server in each of them, and good luck debugging it when one implementation is broken...) As a technical motivation, HTTPS in an high level protocol, and using it for DNS is kind an overhead. We already have DNS over TLS that is a standadized protocol, that can be used, and that the operating systems are starting to implement. I use DNS over TLS in my local network, but rather than having configured all the computers to use it I have configured a local DNS server that encrypts the requests, for every host in the network, and also filters trackers and ad servers. Thus I don't want Firefox to mess aroung with my local network configuration that is fine.