You just make Gargan an insane experiment gone wrong, made to simply compete or humiliate Spidey, but goes psychotic and just wants to wreck shit all power crazed

Spidey beats him with brains vs brawn, Scorpion develops a grudge, keep him strong, a threat, and willing to kill civilians, doneski

It doesn't need to be complex, the problem is Spidey writers love to make villains job too hard and become punching bags