Dumdum As in, you can specifically select domains to deny/allow similar to something like uBlock?
Yes.
Dumdum I've not used those three services before, but are they more configurable than these Mullvad DNS options?
Yes, they are. Think of those services (AdGuard DNS, NextDNS, ControlD) as if you were running your own pi-hole instance (but of course it isn't yours per se, and you must trust those services to respect your privacy).