As for as I remember in comics it’d be Batman with IQ more than 190, I don’t exactly remember how much tony had but in movies (MCU) it’d be tony stark because of the following reasons 1)when Agent hill asked him in Avengers that when did he become expert in nuclear astrothermodynamics he answered yesterday night.
2) Building mark 1 in a cave with not much of Technology is no ordinary thing at all.
3) Knowledge of AI and NanoTech and Integration of those two
4) Brilliant war strategic and tactical mind he had.
And many more.

Batman is a god there is no other super hero even close to his intelligence,planning,tactics,fighting,stealth in entire MCU and DCEU

Ironman is more smarter than bat man

Bat man is also a good strategist