Many commenters assume fallback behavior exists between DNS providers, but in practice, DNS clients - especially at the OS or router level -rarely implement robust failover for DoH. If you're using cloudflare-dns(.)com and it goes down, unless the stub resolver or router explicitly supports multi-provider failover (and uses a trust-on-first-use or pinned cert model), you’re stuck. The illusion of redundancy with DoH needs serious UX rethinking.
I use routedns[0] for this specific reason it handles almost all DNS protocols; UDP, TCP, DoT, DoH, DoQ (including 0-RTT). But more importantly is has a very configurable route steering even down to a record by record basis if you want to put up with all the configuration involved. It's very robust and is very handy, I use 1.1.1.1 on my desktops and servers and when the incident happened I didn't even notice as the failover "just worked". I had to actually go look at the logs because I didn't notice.
