public class DrawRectangle : MonoBehaviour 
{
    // ...

    private Rigidbody2D _rigidbody2D;
    private BoxCollider2D _boxCollider2D;
    
    private bool _simulating;
    public bool SimulatingPhysics
    {
        get { return _simulating; }
        set {
            _simulating = value;
	    _rigidbody2D.bodyType = value ? 
                RigidbodyType2D.Dynamic : RigidbodyType2D.Static;
        }
    }

    private void Awake()
    {
    	// ...
        _boxCollider2D = GetComponent<BoxCollider2D>();
        _lineRenderer = GetComponent<LineRenderer>();
        
        _rigidbody2D.useAutoMass = true;
    }

    public void UpdateShape(Vector2 newVertex)
    {
        // ...
		
        // Update the collider
        var dimensions = (_vertices[1] - _vertices[0]).Abs();
        _boxCollider2D.size = dimensions;
    }
}