[[If they did not get a CRBA till 1986 that means that Cruz was designated a Canadian at birth.]]
There is nothing that bars someone who was a dual citizen from being president if the dual citizen was a US citizen ‘at birth’ or ‘by descent’
It comes down to ‘allegiance’- A child born to a US citizen is under that sovereign parent’s ‘allegiance to the US’ while the child is still a child (until age 18 or whatever age it is)- After age 18 the child, now an adult, can, if they so choose, expatriate themselves by going through a process, and by swearing allegiance to another country if they wish- That is a right protected by constitution/statute- the right of a Sovereign US citizen to expatriate themselves if they so wish- but it is a process (or act so obvious that there is no question the person ‘means to expatriate themselves’ such as treason, joining another country to fight against the US etc)
While it is murky, the evidence weighs now more o n the side of a child being under the allegiance of the US if born to a sovereign us citizen either here or abroad-
What you're saying is that Winston Churchill could have been POTUS, or even now Queen Noor's son's are eligible.
Pretty sure that is not what the Founder's had in mind with NBC,