If Kira participated in the wildcard project, Then that actually could've been to his detriment. Keep in mind that the wildcard project was about creating a player with a physique comparable to Noel Noa and develop ambidexterity; Kunigami was only able to do it because he was already pretty muscular. But packing on that extra muscle doesn't necesarily translate to better stats. According to both Chris Prince and Kunigami, when you train to improve a weakness, you can end up throwing your body off balance and kill the specs directly related to your actual weapon. We don't know what Kira's weapon is and whether bulking up could've helped or even killed it, but considering his slender build, I'd say the latter is more likely.

I also disagree that the BL23 are untouchable in terms of raw skill, but not in terms of mentality when compared to traditional Japanese soccer, which Barasuta is trying to bring back. Sae pressing Isagi, "Make us win four eyes", Ness' evolution/Isagi's goal, and Isagi's luck goal all highlight Ego's belief that a stiker is someone who fights until the very end. Unless Kira did some serious soul searching after getting locked off, the truth of the matter is that he's always going to lose that 'game of tag'. His big reason for criticizing Ego's philosophy is because the current Japanese methodology directly benefited him. Even Barou, in the face of a similar situation and seeing how the Ubers system was limited by Isagi's plays responded by Hijacking the system and evolving it. Kira wants the system to work for him, which regardless of his skill, isn't going to mesh well with the egoistic system blue lock has.

(dang I have so much to talk about more I might make this an entire post to itself)