Another myth of throwing a hook is it’s all in the wrist. It’s not. You can do serious damage to your wrist if you’re repetitively cranking it back and forth while holding a 16-pound object.
The main aspect of the release is your fingers. Your thumb should exit the ball first, leaving your two bowling fingers to control the hook of the ball (your index and pinky fingers can also affect the hook).
When releasing the ball, you should naturally flick your fingers as you let go. Not too much, but you should be able to feel some control over the ball as you let it go.