It’s not a cliché when people say that quarterback is the most difficult position in sports.
Quarterbacks spend hours studying the fronts, coverage and personnel of a team so that they are prepared for every possible scenario they possibly can for their next opponent.
Then, 30-plus times a game, after gathering as much information as they can to help them, they have to be able to call the play, line the offense up correctly (sometimes with shifts and motions), identify the look of the defense, set the protection, potentially change the play, snap the ball in time, identify the blitz and know if it holds up to the protection, identify the coverage, go through the progression based on said coverage, make the right drop for the route they want to throw and deliver the ball on time and with accuracy, all in about 45 seconds.