Thus citizens before, and citizens after the Constitution was crafted and adopted by all of the states, of the now established United States of America.
I have not ignored that at all. This aspect which you now mention is precisely my point. We ceased being "Subjects", defined by British Common Law, and we became "Citizens", defined by Natural Law.
You will note that the Declaration of Independence itself specifies we are following "the law of nature, and of nature's God..."
We tossed out British Common law regarding the nature of our citizens. Some people revived it (William Rawle, et al) and led others to believe it was the model for "citizen", but this is incorrect. Our model for "citizen" is natural law as articulated by Vattel.