Mate in 5 was pretty easy!
Improvers POTD #21 (05/03/25)

I don't really get the second one. Isn't any King move winning after 4. h4+?
I was confused on the same thing.Kg4 does not seem necessary.Doesn’t Kh2 also work

I was confused on the same thing.Kg4 does not seem necessary.Doesn’t Kh2 also work
Kh2 was the move I played instantly. I tried to figure out why it didn't work for a while before I finally gave up and checked with an engine. It seems like that part of the puzzle is cooked unfortunately. It's still a good puzzle. My guess is that Kg4 is the only option that makes the rest of the puzzle forcing which is why it was chosen as the answer despite being really unintuitive.
Convert the Endgame: