Are there any examples of "lowest ranked but secretly OP main character" done right?
Past Stardust Crusaders when the heroes' powers became less utilitarian and more elaborate and the battles were less about getting the team's big gun close enough to unleash a barrage of punches, JJBA's fundamental gimmick has always been about clever applications of what you can do, rather than an outright DBZ-style slugfest or the usual LN inanity.
So even characters that don't have the stock standard close-range punch ghost are still viable combatants in most situations.
Hell, even during Part 3 when Jotaro lacked the enormous applicability of Hamon like Joseph's, all of his fights were essentially a desperate scramble for survival and outmaneuvering his opponent to actually be able to effectively strike his opponent, essentially being Jonathan Mk. 2, rather than just tanking and swaggering into the enemy barrage.
Likewise there was that manga about that girl who had the powers of banana manipulation in a world where people had shit like super strength or hydrokinesis.
>tfw Kiss x Death is incredibly mediocre but you keep reading it anyway