Soveit "plans" to bring communism to Europe were more of an ideaological hoax, to get communists everywhere to do small things for SU and for local population to justify low life standard and lots of work.
IF you look at the reality on the ground, by 1938, the wast majority of Russian Revolution leaders were declared enemies of the poeple and repressed. Much of "revolutionary" changes were rolled back, and overall, SU ceased to really be "communist", just keeping the flag and rethoric, much like todays China is "communist" in nothing but name.
SU was trading a lot with west, and there really was no need for SU to rush into war, it had all the resources needed, and was building up it`s industry, military and diplomacy.
Also, it was wholy unrealistic for SU to win a war against most of Europe, and they were aware of that, hence they chose to cooperate with Hitler, for a time. IF Axis and Allies didn`t go to war, there was nothing SU could really do, and hope to win. Most of what SU would do, would be fighting proxies trying to create friendly regimes like Spanish civil war, Vietnam war, Korean war, ex.