It’s obv Garp no imu rocks or joy boy he is third in the verse for me after white beard and Roger so I can see prime Garp absolutely walking the floor with Luffy s-hawk and dorry
Prime garp could go toe to toe with roger which also means in his prime he could also go toe to toe with whitebeard prime. Meaning Luffy who barely took out a emperor with lots of help by his side, can’t take down his own grandpa