Wall Jump Scripting Help

Hi, Im trying to make a simple fast paced 3D plat former to learn the basics of unity. I wish to implement a wall jump that is relative to the surface the player is standing on so i dont have to create many diffrent implementations of what the player is standing on. This is my script so far...

 using System.Collections;
 
 using System.Collections.Generic;
 
 using UnityEngine;
 
 public class PlayerController : MonoBehaviour
 
 {
 
     public float speed;
     public float jump = 20f;
     private Rigidbody rb;
     float timer = 0.0f;
     bool isGrounded = true;
    
 
     void Start()
     {
         rb = GetComponent<Rigidbody>();
     }
 
  
 
 
     private void Update()
     {
         bool player_jump = Input.GetButtonDown("Jump");
 
         if (player_jump && isGrounded)
         {
             rb.AddForce(Vector3.up * jump);
         }
     }
 
 
 
 
     void OnCollisionEnter(Collision collision)
     {
         if (collision.gameObject.CompareTag("Ground"))
         {
             isGrounded = true;            
         }
         if (collision.gameObject.CompareTag("Wall"))
         {
             isGrounded = true;
         }
 
     }
 
 
 
 
     void OnCollisionExit(Collision collision)
     {
         if (collision.gameObject.CompareTag("Ground"))
         {
             isGrounded = false;
         }
         if (collision.gameObject.CompareTag("Wall"))
         {
             isGrounded = false;
         }
     }




 void FixedUpdate()
 {
     float moveHorizontal = Input.GetAxis("Horizontal");
     float moveVertical = Input.GetAxis("Vertical");

     Vector3 movement = new Vector3(moveHorizontal, 0.0f, moveVertical);

     rb.AddForce(movement * speed);
 }

}

So, My player is a ball and i wish to have it able to wall jump off of a wall. For now it jumps only up and i want to be able to grate a jump that applies a force off the wall. Like in Mario. So how do i create a wall jump that is relative to the surface that the player is standing on?