You haven’t read 1790 and 1795.
1790 says those born to US citizens overseas are natural born.
1795 expands on that and says those born to US citizens overseas are citizens by RIGHT and by DESCENT.
In other words, it is their RIGHT to be a citizen and it is because they are BORN to an already citizen.
Also, the Constitution is not amended by putting into effect the powers granted to the Congress in Art 1, Sec 8. The last paragraph of Sec 8 says that Congress can make all laws necessary to carry out their powers.
So, Congress saw fit to pass those laws to carry out their power to oversee naturalization. To oversee naturalization you have to address both who needs to be naturalized and who doesn’t need to be.
Cruz falls into the category of one who does not need to be naturalized. That is because his citizens was BY RIGHT at Birth and BY DESCENT at birth.
Nowhere does the Nationality act of 1795 use the term natural born Citizen.
In fact, Sec. 3 of the Nationality Act of 1795 expressly states in no uncertain terms that:
the children of citizens of the United States, born out of the limits and jurisdiction of the United States, shall be considered as citizens of the United States: Provided, That the right of citizenship shall not descend to persons, whose fathers have never been resident of the United States: Provided also, That no person heretofore proscribed by any state, or who has been legally convicted of having joined the army of Great Britain during the late war, shall be admitted a citizen as foresaid, without the consent of the legislature of the state, in which such person was proscribed.
Nowhere in the Nationality Act of 1795 does it declare that those children of citizens of the United States, born out of the limits and jurisdiction of the United States, shall be considered as natural born Citizens of the United States