Red, White & Royal Blue by queer non-binary author Casey McQuiston.
It's a romantic novel about the college-age son of the US President who gets thrown together with his UK counterpart - the Queen's second grandson. Their initial competitiveness grows to friendship, and then into something more, with international political implications.
This is just designed to be a fun bedtime or beach read, and I thought it worked really well on that level. My only gripe is that while it gets life in the White House down fairly accurately, there is a huge gap in what life in Buckingham and Kensington Palace is like and even how royal titles work. That aside, it pulled me in with some actual interesting twists and very good characters.