After doing a bit more research, I've come to the conclusion that if Trump accepts this "gift," it will indeed be in violation of the constitution, since it would be considered a bribe from another country. Trump has improved America in a lot of ways already, but he's also made some pretty dumb mistakes, and I really hope that he doesn't accept Qatar's offer. If he does, then...I sure hope he knows what he's doing, because I don't.
I'm glad Trump won in 2024, but I'm also glad that he's not going to stick around forever, because he's nowhere near the perfect president.