2D Movement Controls Like a Dying Fly

I've recently started using unity out side of the occasional messing around, for school and have tried multiple things but can't get it to work as I always get the character Doing circles around the center of the screen.

The two scripts I'm using (I haven't finished the first one):

Character

 using UnityEngine;
 
 public class Go_Towards_Cursor : MonoBehaviour
 {
     public float speed = 5f;
     public Vector2 Momentum;
     private Vector2 NewPosition;
     public float Acceleration;
     // Start is called before the first frame update
     void Start()
     {
 
     }
 
     // Update is called once per frame
     void Update()
     {
         //https://www.youtube.com/watch?v=mKLp-2iseDc
         Vector2 direction = Camera.main.ScreenToWorldPoint(Input.mousePosition) - transform.position;
         float angle = Mathf.Atan2(direction.y, direction.x) * Mathf.Rad2Deg;
         Quaternion rotation = Quaternion.AngleAxis(angle, Vector3.forward);
         transform.rotation = Quaternion.Slerp(transform.rotation, rotation, speed * Time.deltaTime);
         //
         if (Input.GetKey("w"))
         {
             Momentum.x = Mathf.Sin(transform.eulerAngles.z + 90) * Acceleration ;
             Momentum.y = Mathf.Cos(transform.eulerAngles.z + 90) * Acceleration ;
         }
         NewPosition.x = transform.position.x + Momentum.x;
         NewPosition.y = transform.position.y + Momentum.y;
         transform.position = NewPosition;
     }
 }

Camera

 using UnityEngine;
 //https://youtu.be/MFQhpwc6cKE
 public class Camera_Follow : MonoBehaviour
 {
 
     public Transform target;
 
     public float smoothSpeed = 0.125f;
     public Vector3 offset;
 
     void LateUpdate() => transform.position = target.position + offset;
 
     /*void LateUpdate()
     {
         transform.position = target.position + offset;
     }*/
 }