Why is Qxg4 better than Nxg4?

Can anyone recommend me any openings?(Btw my elo is 1900 on chess.com)and iam both a tactical and positional player

Can I understand why there is no focus on taking the pawn on H4? In this position arjun(white) played Qd2. But I don’t understand the logic of this move. To me, it occurs as a blunder cuz once the h4 pawn falls, the g5 pawn also falls and the pawns on the g and f file can easily promote with the help of queen. I need someone to explain to Me why Qxh4 was not even played Btw black just played knight e5 to c6. And white to move so white played Qd2 and I don’t understand why you don’t take on h4. Generally also when I watch Gothamchess there are games where free pawns and he doesn’t even take a plays another move. I need to understand the logic behind these type of play by grandmasters