How do i change the player camera to a free view?

I'm making a game similar to outer wilds where you can go to other planets, I'm doing fine with the scripts, but the biggest problem here is player movement in space.

I don't know of a way to define a player's movement in space, where you can freely rotate and go in the direction you're facing.

need help here

 public class FirstPersonController : MonoBehaviour
 {
 public GravityOrbit Gravity;

 // public vars
 public float mouseSensitivityX = 1;
 public float mouseSensitivityY = 1;
 public float walkSpeed = 6;
 public float jumpForce = 220;


 public LayerMask groundedMask;

 // System vars
 bool grounded;

 Vector3 moveAmount;
 Vector3 smoothMoveVelocity;

 float verticalLookRotation;

 Transform cameraTransform;

 Rigidbody rigidbody;

 public float ZeroG = 5;

 void Awake()
 {
     Cursor.lockState = CursorLockMode.Locked;
     Cursor.visible = false;
     cameraTransform = Camera.main.transform;
     rigidbody = GetComponent<Rigidbody>();
 }

 void Update()
 {
     if (Gravity)
     {
         // Look rotation:
         transform.Rotate(Vector3.up * Input.GetAxis("Mouse X") * mouseSensitivityX);
         verticalLookRotation += Input.GetAxis("Mouse Y") * mouseSensitivityY;
         verticalLookRotation = Mathf.Clamp(verticalLookRotation, -60, 60);
         cameraTransform.localEulerAngles = Vector3.left * verticalLookRotation;

         // Calculate movement:
         float inputX = Input.GetAxisRaw("Horizontal");
         float inputY = Input.GetAxisRaw("Vertical");

         Vector3 moveDir = new Vector3(inputX, 0, inputY).normalized;
         Vector3 targetMoveAmount = moveDir * walkSpeed;
         moveAmount = Vector3.SmoothDamp(moveAmount, targetMoveAmount, ref smoothMoveVelocity, .15f);

         // Jump
         if (Input.GetButtonDown("Jump"))
         {
             if (grounded)
             {
                 rigidbody.AddForce(transform.up * jumpForce);
             }
         }

         // Grounded check
         Ray ray = new Ray(transform.position, -transform.up);
         RaycastHit hit;

         if (Physics.Raycast(ray, out hit, 1 + .1f, groundedMask))
         {
             grounded = true;
         }
         else
         {
             grounded = false;
         }
     }

     else
     {

     }
 }
 public void FixedUpdate()
 {
     // Apply movement to rigidbody
     Vector3 localMove = transform.TransformDirection(moveAmount) * Time.fixedDeltaTime;
     rigidbody.MovePosition(rigidbody.position + localMove);
 }

}