The wikipedia article seems to concur with you, although this seems to be a voluntary policy by CUII, the members could still decide to not wait for any court orders and block whatever they want.
> Daher habe die Bundesnetzagentur die CUII gebeten, die Überprüfung mutmaßlich urheberrechtsverletzender Seiten künftig gerichtlich vornehmen zu lassen.
this is not a requirement, they're just asking. The BNetzA just wants to not deal with it apparently.
- https://de.wikipedia.org/wiki/Clearingstelle_Urheberrecht_im...
- https://netzpolitik.org/2024/cuii-liste-diese-websites-sperr...
Its a DNS based block, so overriding your default DNS server is enough to circumvent it. I think Dns over Https also works.