The 14th is positive law. You can’t make anyone a natural born Citizen through declaring it—It’s self evident. Just as you can’t make a brown-headed cowbird an eagle by declaring it.
Under a precedent going back to 1898, as far as U.S. courts are concerned, Kamala Harris is a natural born citizen.
That is a fact. Opinions of that fact, pretending it is not the case, or looking for excuses that will not hold up will not change it.
If she runs in 2020 the only way to beat her is in the ballot box, and not with legalisms that would get thrown out of court.