That’s because Bavaria is close to the Czech republic and the bavarian/czech border is a well known import corridor. Google further info on that, if you’re interested. Also, I invite you to compare the NRW numbers to the Berlin ones.
This lacks perspective. Border states have "black tar" heroin, which comes from mexico, and is less pure than northeast heroin which is purer and in powder form instead of tar.
Most stuff coming over from CZ is meth and illegal tobacco and fireworks.