If they Puerto Rico wants to become a state, the United States Congress and the president could approve statehood.
However, Congress cannot remove citizenship status from people born in Puerto Ricans, just as they cannot remove the citizenship status of people born in New York City.
Nor could they pass an act that says the children of US citizens born in New York are not US citizens.
Not to be argumentative but you may not have read my complete post. What I am suggesting is after cutting Puerto Rico lose, i.e. they become their own country then FUTURE generations of Puerto Ricans will be citizens of Puerto Rico solely and NOT citizens of the United States therefore they won’t be stripping Puerto Ricans of any US citizenship as they won’t have it to begin with. I believe the citizens of the US must ultimately have the final say over what countries can be part of the Union and I don’t believe that Puerto Rico can or should be allowed to vote itself statehood.