I've also changed to 9.9.9.9 and 8.8.8.8 after using 1.1.1.1 for several years because connectivity here is not very good, and being connected to the wrong data center means RTT in excess of 300 ms. Makes the web very sluggish.
Does that setup fall back to 8.8.8.8 if 9.9.9.9 fails to resolve?
Quad9 has a very aggressive blocking policy (my site with user-uploaded content was banned without even reporting the malicious content; if you're a big brand name it seems to be fine to have user-uploaded content though) which this would be a possible workaround for, but it may not take an nxdomain response as a resolver failure
https://developers.cloudflare.com/1.1.1.1/faq/#does-1111-sen...
I've also changed to 9.9.9.9 and 8.8.8.8 after using 1.1.1.1 for several years because connectivity here is not very good, and being connected to the wrong data center means RTT in excess of 300 ms. Makes the web very sluggish.