You say the 14th gives Congress no additional powers. I would direct you to read section 5:
“Section 5. The Congress shall have power to enforce, by appropriate legislation, the provisions of this article.”
Your main argument is asinine and not worth debating. I’m just pointing out that you couldn’t even get your preemptive arguments right...
All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.-- having
or naturalizedthere means that this cannot be used to let congress define who is natural born, indeed it restricts the states from considering Dred Scott's reasoning that a slave cannot be a citizen [extending this, the not-citizens of the emancipated slaves] because they were property [and, of course, the product of two pieces of property could not somehow become a citizen by "accident of birth"].
So, again, no new powers were assigned to congress with respect to citizenship.