I've been here for a decade, and sadly I feel the issue is upward mobility for skilled workers. Unless you're working for an intl company, with ex-pats in positions of leadership, your chances of "getting ahead" are going to be limited, especially when you're competing against natives. The reason is sadly, the culture is very reserved and cautious, so as an "outsider" it's going to take A LONG time before you can be…
All of this to say that your observation in Germany doesn't sound that different from mine in the US (been here for over 20+ years; been in a manager/director role in data for almost a decade).