Quad9 is based in Switzerland, so the German court should only have jurisdiction over whatever servers are in Germany. It seems like the worst case scenario is that Quad9 shuts down their German servers, but still serves German requests from servers in neighboring countries.

That said this is still terrible and I hope the German court reconsiders their decision. The free flow of information is more valuable than protecting copyrights, because the former benefits many more people. Most of the copyright holders who feel threatened by piracy are not even German! The court is protecting big American businesses over individual Germans.