I'm Polish, and if I'm honest with you, I don't get why people visit Poland for tourism. And I especially don't get why someone would go to Poland just for one city as everything in this country is spread out. It's not Czechia where you can go to Prague, see tons of stuff there, maybe some towns around it, and get a good feel for this place. In Poland there are multiple "big" cities, which makes it so that none of them are that dominant and none of them are that great of a tourist attraction.

And I wouldn't recommend someone just to go to Krakow as you will run out of stuff to see there in 1,2 days. Unless you also travel to Wieliczka and Energylandia. Same with other cities in the country.