All good, but again, the Russian rationale is not economic or political, it is deep seated psychological resentment of the American republic and electoral tradition as a whole, which would be there regardless of who was running.
The Kremlin has a vested interest in diminishing the appeal of democracy for the sake of self-preservation. They fear the prospect of their own people rising up in demand of freedom, while the Russian people are embittered by their current incapacity to do so. So they take comfort in the midfortunes and chaos of free societies. It postpones the uncomfortable self-reflection they have to deal with on their own. Schadenfreude.
All of that is true, and it does explain their meddling in our elections. But I will come back to the fact that I don’t think that they could really affect the outcome, nor did they believe that they could affect the outcome. And if they did, they most certainly would not support Trump, because they are rational actors. Rational actors don’t support people who can destroy their own economy versus people that will continue policies that at least don’t hurt them.