The German high court now suggests that if ad blockers manipulate a site’s structure in ways that violate copyright integrity, they could be deemed illegal.

Now, I’m no legal expert, particularly not in the workings of German copyright law. But an ad blocker does not “manipulate a site’s structure”, so copyright seems like very shakey grounds for a legal argument. All adblockers do is block connections to specific domains, and then what you see is what the website’s server spits out without downloading info from those outside domains. AFAIK there is no adblocker that is editing a website’s actual code, but maybe some of the advanced YT adblockers are doing that, idk.