which means the USK not only kinda chooses themselves by what criteria the games get rated, they are also prone to bribes by shady AAA companies
That's wrong. . . The basis is the law for the protection of minors. (Jugendschutzgesetz )
The USK only checks the games but does not give a rating.
This is done by a representative of the highest state youth authorities. (Vertreter der Obersten Landesjugendbehörden )
But these are just details and we should get back to the actual subject.