Ball continuously accelerating even after releasing the key

Here’s my BP:

So the value of my torque strength is 10 units. (I’ve tried changing the value, from 1 to 50.) Now when I press WASD, the ball moves very quickly and doesn’t instantly change directions when I press other keys. As I hold down the input for the ball movement, the ball rolls faster and faster. I would like the ball to roll up to a certain speed and go no faster and stop when there is no input being pressed.
That way I’m unable to move the ball on the paths I created using extrude.
What can I do to make the ball move fine?