InputHandler.cs

using UnityEngine;

public static class InputHandler
{
    private static readonly Camera MainCam = Camera.main;
    private static int _frameCount = -1;
    private static Vector3 _lastPos = Vector3.zero;
    private static Vector2 _delta = Vector2.zero;
    public static Vector2 MouseDelta => _MouseDelta(); 

    private static Vector2 _MouseDelta() {
        if (_frameCount == Time.frameCount)
            return _delta / Time.unscaledDeltaTime;
        if (Input.GetMouseButtonDown(0))
            _lastPos = MainCam.ScreenToViewportPoint(Input.mousePosition);
        if (Input.GetMouseButton(0)) {
            _delta = MainCam.ScreenToViewportPoint(Input.mousePosition) -
                     _lastPos;
            _lastPos = MainCam.ScreenToViewportPoint(Input.mousePosition);
        }

        _frameCount = Time.frameCount;
        return _delta / Time.unscaledDeltaTime;
    }
}

PlayerMovement.cs

using static InputHandler;

public class PlayerMovement : MonoBehaviour
{
    [SerializeField] private Vector2 sensitivity;
    private float xMove, yMove;
    private Rigidbody2D rb;
    
    private void Start() {
        rb = GetComponentInChildren<Rigidbody2D>();
        rb.centerOfMass = Vector2.zero;
        rb.inertia = 1;
    }

    private void FixedUpdate() {
        var angles = rb.transform.eulerAngles;
        angles.z = Mathf.Clamp(
            angles.z > 180 ? angles.z - 360 : angles.z,
            -45,
            45
        );
        rb.transform.eulerAngles = angles;

        rb.AddForce(new Vector2(xMove, yMove));
        rb.AddTorque(Mathf.Abs(xMove) > 0 ? xMove : -angles.z * 2f);
    }

    private void Update() {
        if (Input.GetMouseButton(0)) {
            xMove = MouseDelta.x * 10f * sensitivity.x;
            yMove = MouseDelta.y * 16f * sensitivity.y;
        } else
            xMove = yMove = 0;
    }
}