No amount of Stark tech can bridge the gap against a Kryptonian powerhouse.
Tony Stark is perhaps the greatest engineer in all of fiction, but Superman is simply in a different league. Even Tony's most advanced suits โ the Celestial Buster, the God-Killer โ are designed for specific threats within the Marvel Universe. Against a being who can benchpress the Earth, move at light speed, and is powered by an endless energy source (the sun), technology runs into hard limits.
Superman's speed alone is the fight-ender. He moves and processes information at speeds that make Tony's AI reaction time look like dial-up internet. Before JARVIS or FRIDAY can even identify Superman as a threat, Clark could dismantle the suit at the molecular level.
With absurd levels of preparation and knowledge of Superman's weaknesses (kryptonite, magic, red sun radiation), Tony could theoretically build a counter โ he's done similar things against Celestials and World Breaker Hulk. But in a standard encounter, Superman outclasses Iron Man in every physical metric by orders of magnitude.
Tony's genius is his superpower, and his suits have gone toe-to-toe with celestial beings. Given knowledge of kryptonite, he could engineer a suit that exploits Superman's weakness. His AI systems provide tactical analysis in real-time, and his nano-tech can adapt to any threat pattern.
Superman is faster, stronger, and more durable than any Iron Man suit by orders of magnitude. He can flash-blitz and dismantle the suit before Tony's systems even register the threat. Heat vision can melt armor, and freeze breath can incapacitate systems. Superman doesn't even need to hit Tony โ he could just hurl the suit into the sun.
Superman wins decisively. Tony Stark is a genius, but he's fighting someone who can think and move at lightspeed with planet-breaking strength. The tech gap that Iron Man uses to compete in the Marvel Universe doesn't translate when the opponent is a solar-powered alien god.
Iron Man also fights
Superman also fights