For someone to be truly transgender, they will have to have completed their metamorphosis to the other gender. The halfway shit doesn’t count. So, for instance, the college swimmer who takes hormones for one year and then competes in women’s category should not be allowed. If that same swimmer has had the reassignment surgery, then they aren’t fecking around.
I would add that boosting hormone levels to maintain the transition would also count as an artificial enhancement. If you have elevated levels of testosterone or estrogen, you are ineligible to compete, just like any other PED.
At a basic level, a person has XX or XY chromosomes. We can get away from “male” and “female” categories and make it XX or XY. That cannot be changed by a person with surgery or drugs, and it is what it is. It has nothing to do with your identity, or your feelings, it’s just science.