Lewis has been TKOd/KOd several times, he doesn't have a great chin. Ngannou on the other hand ate Stipe's hardest shots all fight and even while GASSED still wasn't phased by them.
Lewis doesn't really have a path to victory, their first fight was an anomaly and using anything from that fight to imagine how a rematch would go is pure lunacy and foolishness.
Ngannou by KO