Here's a thread on just some of the males who have gone on to win women's sports events - including how they performed in the men's category before they started identifying as women

2017: CeCe Telfer is ranked 390th among male NCAA Division II athletes in the 400m hurdles category
2018: Telfer 'transitions'
2019: Telfer is national NCAA Division II women's 400m hurdle champion
2021: Telfer hopes to qualify for the US Olympics

1998-2012: Laurel Hubbard fails to qualify for a single international men's tournament as a professional weightlifter
2013: Hubbard 'transitions' (aged 35)
2014-21: Hubbard qualifies for 11 international women's tournaments, including the

2013-15: Hannah Mouncey made 22 appearances for the Australian men's handball team, scoring 0 goals
2015: Mouncey 'transitions'
2018: Amid controversy, Mouncey is allowed to play 6 times for the Australian women's handball team, scoring 23

Pre 2015: Golfer Hailey Davidson won 0 men's tournaments (in fact it doesn't look like Davidson even qualified for any tournaments)
2015: Davidson 'transitions'
2021: Davidson becomes the first male to win a women's professional golf