the hunger when darkseid fought galactus was non cannon and its already stated that spawn has powers above and beyond the normal universal laws, im not saying he'd win but im asking how can galactus kill him if heaven and hell cant even do it, and those powers he showed even during the second age where probably the tip of the ice berg some of the beings in the spawn universe where not that powerful could still cause stars to go nova and the really really powerful ones where nearly totally indestructable look at malbolgia even when he was at his weakest he still nearly killed spawn and he DID kill angela you shouldnt count out spawn out just yet.
also im sure spawn can also increase his powers by the absorbing of sins and of power he did what galactus did in mephestos realm but spawn did it in a realm that made mephesto's look like a playground probably to a guy that made mephesto look like a handpuppet, and then he can absorb sin for all we know galactus is full of it and it would work against him.