From what I’ve read of Stalin, I think his attitude towards attacking Western Europe could easily go either way. On the one hand, he was an “enlightened” despot whose primary goals were to industrialize and reform the Soviet Union to become a world power, to gather the lands of the old Russian Empire that had been lost during the RCW, and to create an obedient, unified society that believed in the doctrines of Marxism-Leninism. Additionally, and quite rare for a man of his stature, he was also able to realize when mistakes had been made, and to adjust his strategy accordingly. On the other hand, he belonged to a generation of Soviet leaders that interpreted the “revolution” as a world revolution, one that could be realized through military action. In this mindset, if the revolution does not expand, it will be smothered by capitalist encirclement. Stalin was also a gambler, albeit one that preferred medium-risk gambits with potentially high rewards. His foreign policy before June 22, 1941 and after WW2 show time and again that Stalin was willing to take a bold move, if the chance of failure and personal risk to the USSR was minimal. Even the Nazi-Soviet Pact of 1939 could be seen this way, with Stalin assuming that the French would stand up to Hitler and fight him to exhaustion before any of his eastern ambitions could be realized, leaving Stalin to keep his gains.
However, the big problem with this question is that I don’t know what context Stalin is making his decisions in this TL. You can only take forensic psychology so far in these situations. The state of Hitlerless Europe would be fundamental to Stalin’s thinking of the Soviet Union’s foreign policy. If we have the ultra-optimistic outcome of Europe consisting of a constellation of happy, prosperous liberal democratic republics that are all well-armed, Stalin may be deterred to a few small wars with some of the western republics, depending on just how threatening the capitalists are being. However, if we have a situation with a sullen autocratic Germany, London and Paris at each other’s throats, and an Italy spitting in the faces of all three, a clever manipulation of the players may allow the USSR to become a regional hegemon in Eastern Europe. If an actual war breaks out between the imperialists, well, then the sky’s the limit.