Change bouncing angle with touching speed

Hello, i'm making a pong game, it's a natural physics bouncing based game

however, the bouncing angle of the ball on the paddle is always the same and causes a kind of a loop

my idea is:

3 colliders in paddle (Left, center, right)

the left collider bounces the ball in an angle of (-150 to -60) [random] the center collider bounces the ball in an angle of (-10 to 10) [random] the right collider bounces the ball in an angle of (60 to 150) [random]

the ball's angle changes to these no matter what was the previous angle so 3 scripts attached to 3 colliders this way;

 var b : Rigidbody;
 
 OnCollisionEnter () {
 b.rigidbody... NOW WHAT? this is where i'm getting stuck
 }

PS: i want the ball to keep the same speed

What do you suggest?

Thanks in advance xD