I think before 1949, exhaustion, lack of a real threat, and a recognition of history since 1814 probably helped deter any desire to invade Russia.
I’d wonder too about the suggestion that Stalin was working his way toward a full takeover of Germany. Is that where the Berlin blockade etc. were headed?
No idea. But I have often wondered about that very same question. Why he did blockade Berlin but failed to take advantage of that after the war. If I recall correctly, the blockade was lifted only after he died.
IMHO, Stalin was one of the greatest rats in all of history. But, he was also one of the most interesting.
Could he have been scared to actually take more territory after WW2? If so, he would have been scared that his own people would not have backed him.
During the war, it was easy to make big moves without the fear that his people would back him. Because they were at war, anyone who refused could be executed quickly and easily for treason. But once the war was over, it was a very diff story.
It was also very interesting what happened when he died and how everyone was still terrified of him - even of his corpse!
There was never a period when we could have exterminated the Soviet Union. The exact number is classified but the best estimate is the United States had twelve atomic bombs in 1947. They could have been the basis of a major attack but they wouldn’t have exterminated the Soviet Union. Especially when you consider the difficulties in delivering them to targets in the Soviet Union and the fact these were early fission bombs.
A lot of people forget there was a successful German invasion of Russia in World War I.