Berlin is one the cheapest capital cities in Europe. As such it attracts a huge amount of immigrants. That low cost is reflected in the pay. An experienced full stack developer would be fortunate to get 90-95k euro annually. That is plenty of money if you intend to stay in Berlin, but is not something you can save up and build a future with or transfer to another country. Also, housing is a huge problem there and it can take 6 months to find even a basic flat. I am an American developer that lived there for many years and my co-workers were usually Turkish, Polish, Ukrainian, Iranian, Russian, Lebanese, and now Indian. It was rare to find an actual German coder.

I had a hard time with German work expectations and management style. Also, their engineering approach is thorough but incredibly slow and over-built. The environment is hierarchy and credential based with little room for individual initiative or creative problem solving. I was used to improvising, experimenting, and thinking outside the box. It was not a good fit.

Your first sentence is a bold claim considering the current state of the housing market

Where do the German coders go though?