@Rooftop concerning your post: Restricting a Qube to selected websites
Here, beside the DNS setup are you also interested in testing a pi-hole setup for black-/white listing of websites? I would love to have this as a standard option(!) for Qubes OS. At least a community doc to simple setup pi-hole in Qubes OS.
Pi-hole offers so much more like RegEx, Punycode and Emoji-Domains blocking and a super nice and easy web interface.
Interest, time?