The USSR has to fare substantially worse, even though the Allies still win. This puts the whole European war behind the OTL schedule, and probably also has the consequence that Berlin and another German city at least get nuked.
It also means the Western Allies have much more say in what happens with Poland. Given that the whole schedule is late, they probably still have around 4-5 unscathed paratrooper divisions in 1945 (One of which entirely Polish), and they use them to secure Warsaw, for instance. Boots on the ground mean decisional power. The Westerners, for some reason, decide that they want to keep Gdansk separate from Poland.
The Poles don't like the continued existence of the Free City, but they will accept it if
a) it is free only in name and actually a Polish protectorate, and
b) they don't lose so much territory to the Soviet Union, while at the same time they gain territory at the expense of Germany as per OTL.
It is possible, under this scenario, that Gdansk's territory gets enlarged to the East. A reason for the Westerners to keep it formally independent might conceivably be to maintain a haven for a German minority in the approximate area of Eastern Prussia, and while Koenigsberg would end up in Poland and be known as Krolewiec by now, it is possible some border territory gets added to Gdansk.