And superman has to try to process things quickly so his reaction time isnt fast like the flash.Truth of the matter is Supes is always getting stole on cause he's arrogant
He's practically invincible and so he never feels the need to use super speed to anticipate or dodge any blows
So again, a dude that's a god going up against a man in a batsuit, last thing he's thinking is that he can be harmed by the Bat. Which is why he was continuously caught off guard. It was his own hubris that made him get caught with his pants down
The flash can process information so fast that time seems to stand still while he's thinking, superman can do the same but he has to focus to do it so it's not automatic like flash. You can definitely pull a fast one on supes if he's not expecting it.