It’s ironic to see a guide to securing anything recommend using plaintext MITM-able DNS rather than instructing users to build and configure a safe DNS-over-HTTPS resolver to the exact same IPs.
GP's point is that if you want to secure DNS, it's a bit more involved, hence the build in "instructing people to build and configure a HTTPS resolver".
I don't actually use this, as my home router handles DNS over TLS for everything, but a quick google search turns this up: https://blog.because-security.com/t/use-cloudflare-dns-with-....