What perks or items would you recommend for keeping a squishy human powerful in dangerous shonen jumps while still keeping them a normal guy?

Whether it is being so filthy rich that you can hire some of the strongest fighters in the setting, some kind of genius/tech that's good for keeping up without reaching the levels of "this guy doesn't feel human anymore" that you see in some interpretations of Batman or Lex Luthor...

Just, what would you recommend for this kind of vibe?