Genetic (XY) men, who are truly gender dysphoric, take estrogens as part of their transition. So they are feminized. But even so, you’re assuming that men are inherently better athletes than women. That’s not necessarily true. Trained women are formidable. If you were around in the 70’s, you’ll remember Billie Jean King wiped the court with Bobby Riggs in their boy v. girl tennis challenge.
Not to go off topic, but fillies run against stallions all the time in thoroughbred racing. Though no filly has won the Triple Crown, they have won the Kentucky Derby, the Preakness, and the Belmont. And they’ve won steeplechase competitions. Heck, if horses can do it, why not us?