the suggested move f5+ is definitively looser.
I like it as it is. Its either drawing or winning for white.
white cannot win. black win always
the match is: f5+ gxf5, gxf5+ Kxf5, the black win
after f5+ gxf5 you play gxh5. black can
Yes it's fine. 1.f5 and white wins due to his resulting outside passed pawns