I know nothing of this boxer, but a Trans boxer would have several advantages outside of hormone levels. Physically, males are much better suited for boxing than females. They have larger hearts, lungs, longer arms, bigger hands, and hips more in line to directly send power from punching and keep in balance. Muscle and mass aside, men are better suited at punching, and those advantages don’t go away with hormone blockers.
As to hormone therapy, do you think a professional m2f Trans athlete is going to be taking enough blockers to be towards the lower end of female testosterone, or taking just enough to be in the high end? This is a completely separate argument from the first point I’ve made, but im just curious as to why you would assume it nullifies all the testosterone. You have to have some in order to live. Your bones will go to shit, your heart won’t work right, and you won’t be able to make enough blood cells. Along with muscle loss, fatigue, and other issues. Hormone therapy will not take you down to 0 testosterone.