How does your tier/class of definitions explain/reconcile that the explicit and deliberate wording of the Constitution distinguishes ‘citizen’ for congresspersons and ‘natural born citizen’ for POTUSA?
A citizen of any of the three mentioned in the Constitution is eligible for offices that designate that the person must be a citizen. Citizen is not a separate category it includes naturalized and natural born and those who were citizens at the adoption of the Constitution. Obviously.