The whole topic is pointless.
Yalta had determined what the post-war borders would be and the British, Americans and Soviets all honored those terms quite scrupulously. So unless someone can explain why Stalin suddenly wants to throw out an entire series of arrangements which he clearly approved of over a few scraps of Denmark...
(Hits the head against the wall)
WI a different Yalta conference determines diferent post-war borders giving the USSR control over Denmark, and extended soviet control of Germany up to the Danish border, maybe including, say Wilhelmshave?
Say Stalin belives Hitler is planning to attack the USSR in 1941, the Red Army defends better than in OTL and isn't taken by surprise, the Germans still advance but at a slower rate and by winter they are way more to the west than in OTL. Soviet and Germans offensives and counteroffensives happen along the eastern front but, overall, the Soviets are fighting more west than in OTL and reach, say, Poland, sooner, maybe even in 1944 if possible.
At the same time, Hitler doesn't declare war on the USA after Pearl and orders the Kriesgmarine to do what they can to avoid a casus belli with the USA. The Americans eventually enter the war, but they have less buildup time in Europe, the strategic bombing campaign starts later and they can't deceive the Germans as well as in OTL regarding the location of the ATL D-Day. The Germans also get somewhat luckier in the Western front, slowing a bit more the Western Allies' advances.
So, when Stalin, Roosevelt and Churchill meet in an ATL Yalta (or where ever) Stalin has a better negotiation position and tries to get a North Sea port for the Soviet Navy. How likely is it, and which butterflies might it have?