but Qf3 works even though Qg4 doesn't
bad puzzle

No, it's correct.
I solved it in 30 seconds after trial and error with Nxc7, but at the end I found the right sequence.
Qg4 is an engine move, not a human move.

Qg4 only works if the opponent does the same thing and plays d5. But they won't. They'll play Qh6.
Qh6 d4 and white is +2 lil bro

HOW IS IT 4390
after 3000, puzzles are almost the same again and again, just memorize and ez rating

I messaged Dane Mattson, @Fischwitsch, who is the puzzle curator for the Daily Puzzle.
He says yes, the puzzle has a problem because there are two good starting moves. So, the OP here is right.
https://www.chess.com/puzzles/problem/2053220 in this, Qg4 and QF3 works and even though I got it right, this should be reported