The throwing motions are more similar than you think. There is still an “equal and opposite”. There is still a stride and a weight shift from back to front. There is still "hip and shoulder separation.
What’s different is everything is usually more abbreviated. The stride is shorter, the arm path is shorter and so the glove arm extension during “equal and opposite” is shorter, etc. The reason for all of this is two-fold. First, the football is heavier than a baseball. When lifting or throwing an object, the body naurally keeps heavier objects closer to the center of the body than lighter objects. Second, quarterbacks usually need to get rid of the ball faster than does a pitcher - for obvious reasons that usually weigh between 225 and 300 lbs.
The nice thing that throwing a football does is it gives you immediate feedback on your mechanics - it’s more difficult to throw a good spiral if you mess up your mechanics.