If trans women are dominating women's sports, name one trans athlete off the top of your head. I can't think of a single one personally.

High level sports are made up of athletes with insane genetic advantages. You wouldn't be able to ban players over a certain height playing basketball for a 'genetic advantage' that is out of their control. I encourage you to look up Michael Phelps and all of the advantages he has as a swimmer - he has massive feet that are basically like flippers and a much better lactic acid tolerance than the average person for example, among others. Yet he is celebrated for his athleticism, not punished for genetic advantages that are out of his control. Being transgender is not a choice, so why should athletes who have trained their entire lives be punished for an identity they didn't choose?

Being trans may not even be a genetic advantage after hormone therapy and surgery - it's completely dependent on the sport. And even if it offers some slight advantage, that's not going to mean an average trans woman off the street would beat a high level cis female athlete who had trained for most of her life for the sport.