Actually, there is no need to “fix” anything, the system we have now is perfect. Women and men compete in different categories according to their natal, biological sex. After all we are perfectly happy to categorise weight lifters, boxers , wrestlers and weightlifters by weight categories, we see the wisdom of separating junior and senior athletes, we accept that it is right to organise Paralympic athletes by their disabilities, so why should sex differences be any different. If trans athletes are good enough to compete in their natal sex categories then that is what they do, if they aren’t good enough then -like the vast majority of the population - they accept that they are not good enough to be elite athletes.
Women’s sports exist so that women can compete, can test themselves against other women, achieve personal, National, international, world and Olympic records, women’s sports do not exist so that mediocre males can steal our scholarships, training programmes, careers, records, and achievements. If sporting achievement means anything it means achievement by effort, skill and application , not by cheating.