I agree with almost all of this. The only thing I think you’re downplaying is the extent to which Trump seems personally beholden to Putin, possibly because he expects financial compensation from Russia.
I agree the US wasn’t exactly heroic in the Cold War, as Oliver Stone’s “Untold History of the US” makes clear. And I agree the Democrats aren’t ideal or progressive. The crux of it is what you say towards the end: you refuse to choose between two evils—which means you prefer to vote idealistically rather than strategically.
In Canada we have the same issue with our dominant Conservative and Liberal parties, and the more marginal, left-wing NDP and Green parties. The latter have no chance of taking over the country, at least not without cataclysmic change to shake us out of our inherent, civilized conservatism. So we face the choice between voting strategically or idealistically, since the dominant parties only take turns being corrupted by power. We vote them out when we tire of their scandals, but because Canadian scandals are relatively mild, we don't go for a more radical alternative ruling party.
I expect it’s the same in the US, except that the Republicans and Democrats have far worse scandals because they have many more temptations in their much more powerful and influential country.