i think about Femlock a lot, mainly because, firstly, if it were a thing, it wouldn't exist on the same basis as the original Blue Lock.
BLLK's argument is based on the fact that Japan has never won a World Cup, but that's not entirely true, to be more precise, it's a half-truth; it's the Japanese men's national team that has never won a World Cup. The Japanese women's national team (Nadeshiko Japan), in fact, won the world cup in 2011.
If, say, the entire cast were women, then winning a world cup wouldn't seem so urgent, wouldn't be the first time Japan did so (at least for the femenine team). What would really motivate Ego to create Blue Lock then? This is just my opinion and the option that I believe could be feasible: to make women's football as important as, or even more important than, men's football.
A large part of Blue Lock's foundation as a project is based on omitting the existence of the women's national team's success, Japan has already won a World Cup, however, this seems not to matter when faced with the possibility of creating the best striker in the world in a men's team. I believe that when we talk about Femlock, we are talking about players who face underestimation not only personally, but also in their entire profession.
Women's football is generally less talked about or looked down upon, ranging from saying that the men's national team games are more fun and/or exciting, to considering the men's national team as the default one and women's as a mere alternative.
If winning a World Cup isn't the goal, then making women's football compete directly with men's football and creating a forward line that can overshadow others (m) could be an alternative. Of course, this would involve rewriting many other things because the characters don't live in a vacuum, and whether we like it or not, their gender will affect their story and arcs.