How to make ball travel in a random directon

I'm trying to make a pong game but when the game starts or resets, the ball will only launch off in the same direction. Only when it hits the paddles, does it will rebound in a random direction. This is the code I'm using:

using System.Collections; using System.Collections.Generic; using UnityEngine;

public class Ball : MonoBehaviour { public Rigidbody2D rb; public float ballSpeed;

 Vector2 direction;

 private void Start()
 {
     transform.position = new Vector3(0f, 0f, 0f);
     Invoke("SetUpBall", 3f);
 }

 private void FixedUpdate()
 {
     rb.velocity = direction * ballSpeed * Time.fixedDeltaTime;
 }

 private void OnCollisionEnter2D(Collision2D collision)
 {
     if(collision.gameObject.CompareTag("Borders"))
     {
         direction.y = -direction.y;
     }else if(collision.gameObject.CompareTag("Paddles"))
     {
         direction.x = -direction.x;
         ballSpeed += Random.Range(7.5f, 9f);
     }

     if (collision.gameObject.CompareTag("RightScoreBorder"))
     {
         SetUpBall();
         ScoreManager.rightPlayerScore++;
     }
     else if (collision.gameObject.CompareTag("LeftScoreBorder"))
     {
         SetUpBall();
         ScoreManager.leftPlayerScore++;
     }
 }

 void SetUpBall()
 {
     transform.position = new Vector3(0f, 0f, 0f);
     direction = Vector2.one.normalized;
     rb.velocity = Vector2.zero;
 }

}