“You must at the very least concede that there was absolutely NO Act, law or provision for dual citizenship at the time the Constitution was signed. It did not exist as an OPTION.”
And thus it was not addressed in the Constitution. There is no prohibition in the Constitution against dual citizens. And if Russia decided today to declare all US citizens to be Russian citizens, we would all instantly be dual citizens - because we cannot control what foreign governments do.
But it also doesn’t affect us, because the Constitution makes no mention of dual citizenship.
Come on. You’re not even trying now. None of that made the slightest sense.