Poland kicked ass all during WWII, during the Battle of Britain, at Monte Cassino, in the sewers of Warsaw, they never gave surrendered.
Russia would lose a lot of soldiers if they dared to try to take Poland again. It’s a price I don’t think even Putin would be willing to pay.
And unlike in 1939, this time Poland would probably have air superiority due to NATO.
It wasn't just at Monte Cassino that the Poles distinguished themselves they fought all the way through the Italian campaign as the right flank of the British Eighth Army.
The Polish 1st Armored Division played a key role in the destruction of the German 7th Army at the Battle of the Falaise Gap in Normandy.