Quite a number of Poles know German
Not anymore. The final death knell for German in Poland was Germany's resistence to Polish labor when Poland joined the EU. Germany (with ally France) did everything it could to keep its labor markets closed to Poles while the UK threw the doors open. The UK acted likean ally, Germany didnt'. By the time Germany had to accept Polish workers.... Poles had lost interest.
Even schools in the Gdansk area have taken German out of the curriculum....