It depends if he can bypass Magellan's poison with his haki or his RS. If so he low diffs because physically Magellan is weak as fuck.
Pre ts G2 luffy put him on his knees and pre ts G3 luffy could push back his strongest form.
Also fire can play a role here, heat usually kills poison so Diable Jambe might be the perfect counter to Magellan's df.