This post has a list of a bunch of drivetrain layouts and their pros/cons:
6 motor drives are very common among higher-level teams, because you often don’t need more then 2 motors for the rest of your robot (assuming you have access to pneumatics). For example in this year’s game, a lot of teams have a 6 motor drive, 1 motor intake, and a 1 motor shooter, with all of the rest of the mechanisms on the robot powered by pneumatics.
The motors are automatically at the highest torque, the torque function can only lower it