In OTL, there was never a significant chance of the German-Soviet friendly neutrality of 1939-41 turning into an outright alliance, because Hitler's #1 goal was ultimately the invasion and conquest of at least the European part of the Soviet Union.
However, what if Germany had been controlled by an ultra-nationalist, expansionist, but non-National Socialist government? Say that this government has no particular interest in lebensraum in the east, but is mainly interested in dominating central and western Europe while also recovering overseas colonies or colonial influence for Germany. Could such a government establish a direct alliance with the Soviet Union? How would such an alliance fare against the UK and France and possibly the USA later in the war? In this scenario, would Japan and Italy most likely be on the side of the German-Soviet alliance, or on the side of the western democracies?
However, what if Germany had been controlled by an ultra-nationalist, expansionist, but non-National Socialist government? Say that this government has no particular interest in lebensraum in the east, but is mainly interested in dominating central and western Europe while also recovering overseas colonies or colonial influence for Germany. Could such a government establish a direct alliance with the Soviet Union? How would such an alliance fare against the UK and France and possibly the USA later in the war? In this scenario, would Japan and Italy most likely be on the side of the German-Soviet alliance, or on the side of the western democracies?