Arkanoid style games get rather boring in Unity 2D physics if the ball ends up stuck in a horizontal or vertical bounce loop. Here's a quick fix:

Unity2D_Arkanoid_Bounce.cs

    [Range(7.0f,15.0f)] [SerializeField] float pushSpeed = 12.0f;
    [Range(0.2f, 0.9f)] [SerializeField] float bounceFudge = 0.4f;

    private void OnCollisionExit2D(Collision2D collision)
    {
        // Prevent ball from following paths that are too close to horizontal
        // or vertical (to prevent boring loops)

        // Get the ball's velocity (after a bounce)
        Vector2 ballVector = myRigidBody2D.velocity;

        // Calculate the angle (in radians)
        float ballAngle = Mathf.Atan2(ballVector.y, ballVector.x);

        if (ballAngle >= 0.0f && ballAngle < bounceFudge) {
            ballAngle = bounceFudge;
        }
        else if (ballAngle <= Mathf.PI * 0.5f && ballAngle > Mathf.PI * 0.5f - bounceFudge) {
            ballAngle = Mathf.PI * 0.5f - bounceFudge;
        }
        else if (ballAngle > Mathf.PI * 0.5f && ballAngle < Mathf.PI * 0.5f + bounceFudge) {
            ballAngle = Mathf.PI * 0.5f + bounceFudge;
        }
        else if (ballAngle <= Mathf.PI && ballAngle > Mathf.PI - bounceFudge) {
            ballAngle = Mathf.PI - bounceFudge;
        }
        else if (ballAngle < bounceFudge - Mathf.PI) {
            ballAngle = bounceFudge - Mathf.PI;
        }
        else if (ballAngle <= -Mathf.PI * 0.5f && ballAngle > -bounceFudge - Mathf.PI * 0.5f) {
            ballAngle = -bounceFudge - Mathf.PI * 0.5f;
        }
        else if (ballAngle > -Mathf.PI * 0.5f && ballAngle < bounceFudge - Mathf.PI * 0.5f) {
            ballAngle = bounceFudge - Mathf.PI * 0.5f;
        }
        else if (ballAngle < 0.0f && ballAngle > -bounceFudge) {
            ballAngle = -bounceFudge;
        }

        // NOTE: Also constrain the ball's velocity to its initial value
        // to avoid unexpected changes of speed
        
        ballVector.x = Mathf.Cos(ballAngle) * pushSpeed;
        ballVector.y = Mathf.Sin(ballAngle) * pushSpeed;
        myRigidBody2D.velocity = ballVector;
    }