So, are you saying that the term citizens of the United States used in the 14th Ammendment is the same as natural-born citizens ?
A natural-born citizen is a citizen from time of birth. Those are synonymous terms. Any definition of a citizen from time of birth is therefore describing a ‘natural-born citizen’.
The only other type of citizen is a naturalized citizen.
The Presidential eligibility reqt is to exclude naturalized citizens.