It was itself months old. Just like in France a century and a bit earlier, revolutions have a way of getting overthrown. And the one that stuck was itself autocratic.

"It's just the nature of revolutions" rings a little hollow when two revolutions had occurred without kicking off a civil war until the Bolsheviks dissolved the democratically elected assembly. Feels rather like creating a power vacuum.

Yes, they did agree to not fight each other and split up some weaker nations (and trade? I’m not sure what you mean by supplying), but calling that an alliance seems like a stretch.

What do you call it when two countries agree to cooperate on military matters, including offensive military actions, up to an including performing a joint invasion of a country with the intention of annexing and genociding it?

Yes, it would have been a very different war if the Nazis weren’t already fighting.

No, as in, "Stalin believed that without American Lend-Lease alone, the Soviet Union could not have survived the war, even with the Western Allies being in the fight"

But, as it was, they were in a stalemate circa 1941 when they started Barbarossa, and the Soviets ended up taking the lion’s share of casualties tipping the balance hard against them. Being a history student, I’m sure you as well have seen actual historians explain that human wave tactics weren’t a thing - Soviets died in spades because they were fighting hard against an enemy that saw them as subhuman.

The Soviets inflicted approximately 50% more casualties on the Nazis (though a roughly equivalent number of total losses due to Nazis being more willing to surrender to Western forces), but suffered roughly ten times the number of casualties as Western forces, or five times if PoW deaths are excluded.

It doesn't have to be human wave tactics to be a staggering display of incompetence that nearly lost them the war.