How do i prevent my character from spinning uncontrollably on a planet?

I am trying to make a space simulation where you can walk around planets and travel to other planets. I am very new to programming by the way. I am/was following Sebastian leagues video for the physics and scripts for the player, but when i land on my planet the player just rotates uncontrollably when i move. (Video: https://www.youtube.com/watch?v=7axImc1sxa0&t=629s)I can look around and rotate on the y axis. I modified Sebastians script so that it would fit with my project. Here is my Gravity script:

 // Update is called once per frame
 void Update()
 {
     foreach (GameObject planet in planets)
     {
         m2 = planet.GetComponent<Rigidbody>().mass;

         float sqrDst = (planet.transform.position - rb.position).sqrMagnitude;
         Vector3 forceDir = (planet.transform.position - rb.position).normalized;
         acceleration = forceDir * G * m2 / sqrDst;
         rb.AddForce(acceleration, ForceMode.Acceleration);
         
         StrongestGravity = acceleration;       
     }

     Vector3 GravityUp = -StrongestGravity.normalized;
     rb.rotation = Quaternion.FromToRotation(transform.up, GravityUp) * rb.rotation;
 }

}

And Here is my Movement script:

{ if (Input.GetKey("w")) { rb.AddForce(transform.forward speed Time.deltaTime); }

     if (Input.GetKey("s"))
     {
         rb.AddForce(-transform.forward * speed * Time.deltaTime);
     }

     if (Input.GetKey("a"))
     {
         rb.AddForce(-transform.right * speed * Time.deltaTime);
     }

     if (Input.GetKey("d"))
     {
         rb.AddForce(transform.right * speed * Time.deltaTime);
     }      

     if (Physics.Raycast(transform.position, -transform.up, out hit, MaxCheckDist))
     {     
         
         Grounded = true;
     }
     else
     {
         Grounded = false;
     }                                 
 }