It is true that the current regulations do not allow the US Federal Reserve to own Bitcoin as Jerome Powell says, but this can be changed. Are these regulations a holy book that cannot be changed? They are simply written by lawmakers, so they can be changed as needed.
Trump certainly knows this and will seek the necessary number of congressional votes to change these regulations to allow the US government to own Bitcoin as a strategic reserve. He will also certainly face opposition from Powell and some senators who do not like Bitcoin, but he will eventually succeed in passing the law, I believe.