Won’t happen. Puerto Rico will be reliably blue. Anyone saying otherwise is a silly person or a lying Democrat.
Puerto Ricans vote blue the moment they get on the mainland at rates just like all other Latino groups (except Cubans). All the arguments in favor of Puerto Rican statehood on the grounds that it will favor Republicans can be used on any number of Latin countries, Latin countries that are “conservative” on social issues (except Argentina I think, or one of those countries, which recently legalized abortion finally), but who vote for absolute corrupt trash every election cycle.
The real problem is the ethnocentrism of these people. Yes, ethnocentrism. A racist adherence to their own people to the expense (if necessary) of all others.
Puerto Ricans will always be Puerto Ricans first, it being their culture and nature, which is why they vote just like any other Hispanic group that moves to the United States.
Problem is, a hell of a lot more Mexicans and Central Americans reside in the U.S. than Cubans and Venezuelans.