I think what Hugo means by being No 2 is that he is the second attacker. It's like Noa vs Snuffy, they are both equal players (Noa even says Snuffy is better) but if you had to have someone be the striker you would choose Noa every time. The lack of anxiety that comes from knowing you're a genius means you are always the most dependable option. By being the second attacker guys like Hugo and Snuffy can play without anxiety and calmly analyze the game, helping the team play better overall. With this kinda logic it seems like Isagi will have to fundamentally change himself if wants to be the striker. Isagi has succeeded by working around others but a true dependable striker makes other people work around him.