The Gdansk old town was tourist-clogged during my summer 2018 visit, so I think time of year is a critical factor there. I had the impression there was a lot of traffic from Scandinavia, or perhaps multiple large cruise ships were in the area. I was in Gdansk for at least 4 nights, and the crowds were there every day.
I would urge anyone contemplating a trip to Poland to dig into a good guide book and use the "In Your Pocket" guides available online for most of the major cities to build a list of sightseeing targets of personal interest. Failing to do that will almost certainly lead to a too-short trip. The Poles have done an excellent job of making their museums and historic sites accessible to English-speakers. Some of those (including the WWII Museum and Solidarity Center in Gdansk and POLIN and the Rising Museum in Warsaw) are extremely large and could be full-day affairs. Folks interested in such things can easily enjoy a week in Warsaw because there are very many points of interest, despite the fact that the rebuilt historic district is modest in size.
I knew about the historic sights before my trip but was surprised at the variety and quality of the food. The best Thai restaurant I've encountered in my 67 years was in Warsaw, and the best Greek restaurant was in Poznan.