Watch Hoppe, Greenleaf and Willie Mosconi. You will see is them flicking their wrist into every shot they make. It’s what they do to make the cue ball dance the way they want it to. When you’re swinging all your wrist and forearm together as one, you can’t flick the wrist like Mosconi because you never cock it back so it can unload and flick into the ball.
You need to begin your stroke not by moving your forearm back, but with a back bend of your wrist that moves your forearm along behind it. At the back of the swing you then release the cocked wrist with a flick and again the wrist leads with the forearm following through the ball.
Let the arm hang loose, now bend the wrist back, farther and farther until pain hits you, then flick it hard, that is your power to your stroke. Your break shot will double in power. You goal is to see how far you can learn to bend your wrist back and that’s how you can measure the force on each shot.