The Hulk's core mechanic ends this fight: unlimited scaling rage. Every joule Superman pours in makes Hulk stronger, angrier, harder to hurt. Superman punches at fixed peak; Hulk's ceiling doesn't exist. That's the whole matchup.
Precedent matters. Hulk fought Sentry—a Superman-tier being with "the power of a million exploding suns"—to a standstill and physically overpowered him. Superman has no comparable track record against escalating opponents.
Durability? Hulk survived a nuclear detonation at ground zero and walked out. He regenerates from near-atomization in seconds. Superman can't kill what heals faster than he can damage it, and he lacks the killer instinct to try.
And Superman's weakness is a rock. He gets exposed to Kryptonite, he's mortal. Hulk's weakness is calming down—the exact opposite of what a brutal slugfest does.
Prolong the fight, empower the Hulk. Superman loses by attrition. Every second favors green.