If Archie is considered a natural-born citizen then he doesn't need naturalization or an act of Congress. Regardless of what that well-known Constitutional reference, People Magazine, thinks.
You are absolutely correct on this particular point. Natural citizens do not need naturalization. (Which is an act of congress.)
They also do not need to make an "election" to remain a US citizen, because they have no ability to be anything but a US citizen.
The Supreme court ruled in that case with the Italian guy, the name of which I have no forgotten, (Roger vs Bellei) that natural citizens don't have to follow any procedures outlined by congress to retain their citizenship.
Any citizen which has to follow a procedure to remain a citizen, is not a natural citizen.
Archie would not be a natural citizen precisely because he would have to follow the naturalization procedures outlined by congress when they passed the law granting citizenship to children born abroad to American women citizens. (Cable act of 1922, and then the Women's act of 1934, If I remember correctly.)
Congress cannot create natural citizens. Congress only has the power to naturalize, meaning to make "like natural."