Rotating object to face mouse with physics isn't working

(First time on the forums) So, I want my players ship to face the mouse using physics and it sort of does... I have posted a screenshot below to illustrate the problem

My code looks as follows:

 using UnityEngine;
 using System.Collections;
 
 public class Movement : MonoBehaviour {
 
     public GameObject thruster;
     
     public float thrust;
     public float torque;
     private float optimalDirection;
     
     public float mouseAngle;
     private float playerRotation;
 
     float angle;
 
     void Start() {
         rigidbody2D.centerOfMass = new Vector2(0.0f,0.0f);
     }
 
     void Update() {
     }
 
     // Update is called once per frame
     void FixedUpdate()
     {
 
         //Enables acceleration
         if ((Input.GetAxisRaw("Vertical") > 0) && (Input.GetKey("left shift")))
         {
             rigidbody2D.AddForce((transform.up * Time.deltaTime * thrust) * 1.5f, ForceMode2D.Force);
             thruster.particleEmitter.emit = true;
         }
         else if (Input.GetAxisRaw("Vertical") > 0)
         {
             rigidbody2D.AddForce(transform.up * Time.deltaTime * thrust, ForceMode2D.Force);
             thruster.particleEmitter.emit = true;
         }
         else
         {
             thruster.particleEmitter.emit = false;
         }
 
         //Allows ship to strave
         rigidbody2D.AddForce(transform.right * Time.deltaTime * (thrust / 2) * Input.GetAxisRaw("Horizontal"), ForceMode2D.Force);
 
         
         //Mouse rotation
         Vector2 mouse = Camera.main.ScreenToViewportPoint(Input.mousePosition);        //Mouse position
         Vector3 objpos = Camera.main.WorldToViewportPoint(transform.position);        //Object position on screen
         Vector2 relobjpos = new Vector2(objpos.x - 0.5f, objpos.y - 0.5f);              //Set coordinates relative to object
         Vector2 relmousepos = new Vector2(mouse.x - 0.5f, mouse.y - 0.5f) - relobjpos;
         mouseAngle = Vector2.Angle (Vector2.up, relmousepos);    //Angle calculation
         if (relmousepos.x > 0)
             mouseAngle = 360-mouseAngle;
 
         //sets 2 variables to aid with figuring out which direction to go
         playerRotation = rigidbody2D.rotation;
 
         //Finds the optimal direction
         optimalDirection = ((((mouseAngle - (playerRotation)) % 360) + 540) % 360) - 180;
 
 
         //Makes ships come to a stand still
         if (Mathf.Round(optimalDirection) == 0)
             rigidbody2D.rotation += optimalDirection;
 
         //Chages velocity when appropriate
         if (Mathf.Round(optimalDirection) > 0 && rigidbody2D.angularVelocity < -5)
             rigidbody2D.angularVelocity = rigidbody2D.angularVelocity / 1.5f;
         if (Mathf.Round(optimalDirection) < 0 && rigidbody2D.angularVelocity > 5)
             rigidbody2D.angularVelocity = rigidbody2D.angularVelocity / 1.5f;
 
         //Applying torque relative to Optimal_Direction
         if (Mathf.Round(optimalDirection) > 0)
             rigidbody2D.AddTorque(torque * Time.deltaTime);
         if (Mathf.Round(optimalDirection) < 0)
             rigidbody2D.AddTorque(-torque * Time.deltaTime);
 
 
     }
 }

I'm not sure what the issue is and was hoping for some sort of solution or alternative, the problem is reoccurring with every side however having the mouse at 90, 180, 270 and 360 degrees relative makes it align perfectly