Don’t be so sure. The difference between modern Russia and the Soviet Union, is the influence of the Russian Orthodox Church. And reclaiming Constantinople has been the goal of the Orthodox for centuries.
To a minimal degree. If Russia are such Christian soldiers, why are they in the Middle East fighting for Iran in the first place? Why is Russia about to screw over their Christian Armenian allies, in favor of Muslim Azerbajan?
What a coincidence. The orthodox church is the reason the Pope wanted Hitler to invade in the first place.