Isnt this what gets all tech companies into trouble all the time. Something objectionable happens (ChatGPT helping someone bulid a bomb for instance) and we go like "Do better".
Here, if any pair of countries have conflicting rules then you simply can't expose your service to both because it's plain impossible for you to block all means of VPN/proxy regardless of how perfect your service tries to detect it. There's no payment, there's no account, there's no anything - you're just serving DNS to an IP that reports to be out of Germany according to German law. At some point it stops being a mistake/malintent of the company and one of the user. Where that transitions probably depends on the person though.
I have sympathy for my fellow man. There isn't enough liability in the world for these corporations.
EDIT: Look at that, downvotes but no rebuttals. (: