is Shintaro fraud?

like before the shintrao vs shingen fight it state indirectly that he is above shingen like he is the bigger brother and somehow survive burn scar as infant and protect his lil bro and have mentality as leader plus his son potential to be better than gun and the biggest one that he didn`t join the the great war or join it but don`t use his full power to not shine over his bro so how tf after all these he barley beat lazy one arm unserious with pre injuried in his chest shingen?? plus got jumped by other members like is that plot hole or i can`t read?? or it meant that in prime her better not in his old version?