Should be noted that Stalin was a Hitler-enabler and early ally, or at least subtle collaborator

lie, western "democracies" refused to ally with stalin against hitler hoping hitler will destroy communism (he kinda did too).

And ukrainians are not some divine angels who would think differently from all soviet republics somehow. They were part of the red army and soviets thought shifting the border away from important city like leningrad, I am not defending invasion of finland I think it was a net negative but maybe that invasion saved leningrad afterall.