Host in Switzerland, that's where Quad9 operates from.
Switzerland has its own DNS blocklist that all ISPs obey. [1]
Quad9 doesn't obey it but I never understood how they can get away with that legally. I'd be interested in an explanation if someone knows more!
1. https://www.gespa.ch/en/fighting-illegal-gambling/access-blo...
Switzerland is not in the EU, thankfully. And it seems to be one of the few places left in Europe where privacy is taken somewhat seriously.