Exactly. There’s absolutely no way of predicting a 10 year old male will be good enough to beat elite adult females.
A lot of work has gone into talent identification for swimming. The vast majority of Olympic medal winners only start winning post puberty. Only the best of the best of the best are winners at junior level and win Olympic medals.
Let’s say you have a 10 year old boy who is a brilliant swimmer. Most coaches know that it means nothing if he doesn’t go through the “right” male puberty to be competitive against men: will he grow enough, mainly.
So how do you predict that the good 10 year old boy, without puberty, will be good enough to beat women at the elite level? He will still need to have the physical characteristics common among elite women athletes. You can’t control or predict that at 10, so what characteristics in 10 year olds do you need? Genetics? Coaching set up? Time to train? All while this boy is dealing with the effects of puberty blockers, then oestrogen?
This would be a 10-15 year cheating project with no way of predicting at the start that you’re onto a sure thing. Most countries who cheat regularly can cheat much more efficiently to win medals than that.