IMHO, the 14th Amendment doesn't create a separate type of citizen so much as it is just an extension of Congress statutory power pertaining to citizenship.
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as Congress can't make such a law as it isn't in their Constitutional powers
Exactly.
Congress has very defined lines of authority, but some people won't even entertain the thought that there are limits to what they can Constitutionally do.
And the ONLY type of citizen they can declare are NATURALIZED ones.
First, the 14th was just that, an AMENDMENT and is not an “extension of Congressional power” -— the 14th is a limit, a prohibition against the States, telling them that they MUST regard Blacks as Citizens. It was NOT “legislation”, but it IS part of the Constitution itself, amending and changing that document.
Also, Congress has declared many types of situations that grant birthright citizenship. The rules for citizenship, when born on foreign soil, have changed many, many times.
Nobody, anywhere, at anytime, has challenged the right and duty of Congress to set the rules for ALL forms of citizenship, and there are only TWO forms:
Natural Born or Naturalized!