It looks like you all had a great time. I love Gdańsk. Was there in the summer. Actually stayed in Poland for over a month and the whole family wants to go back for more. There are some beautiful beaches around Sopot, Gdynia Orlowo cliffs and Hel Peninsula that your kids would love. Did you get a chance to see the most beautiful streets in Gdańsk, Long Market (Dlugi Targ) and Mariacka street (Amber street)? Didn’t see those featured in the video. The architecture is gorgeous in Gdańsk.
What needs to be realized is it's European history and not specifically Polish or German. Before Gdańsk, it was Danzig. But what about before that? Stolen from a tribe? Did the Vikings ever land there? I recall some Celtic artificers being found in the region. Again, you can always go further back and find it was someone else's. But it's always European history