Why there is gameplay difference between those inputs?

Unity Engine
,
1

I created a game in my studies, and theres is a coop mode. Player1 and Player2 have two different inputs methods and they behave differently. Player1 seems to have a delay between the time I press the key and the time to execute the command. Player 2 goes to the direction at instant time.
My code:

   void CalculateMovement()
    {

        if (_PlayerTwo == false)
        {
            float HorizontalInput = Input.GetAxis("Horizontal");
            float VerticalInput = Input.GetAxis("Vertical");
            Vector3 direction = new Vector3(HorizontalInput, VerticalInput, 0);

            if (_speedBoostActive == false)
            {
                transform.Translate(direction * _speed * Time.deltaTime);
            }

            else
            {
                transform.Translate(direction * (_speed * 1.5f) * Time.deltaTime);
            }
                                   
        }

        else
        {
            float _speedboost = 1.0f;
            if (_speedBoostActive == true)
            {
                _speedboost = 1.5f;
            }

            if (Input.GetKey(KeyCode.Keypad8))
            {
                transform.Translate(Vector3.up * _speed * _speedboost * Time.deltaTime);
            }

            else if (Input.GetKey(KeyCode.Keypad5))
            {
                transform.Translate(Vector3.down * _speed * _speedboost * Time.deltaTime);
            }

            if (Input.GetKey(KeyCode.Keypad4))
            {
                transform.Translate(Vector3.left * _speed * _speedboost * Time.deltaTime);
            }

            else if (Input.GetKey(KeyCode.Keypad6))
            {
                transform.Translate(Vector3.right * _speed * _speedboost * Time.deltaTime);
            }
                               
        }

        transform.position = new Vector3(transform.position.x, Mathf.Clamp(transform.position.y, -3.9f, 0), 0);


        if (transform.position.x > 9.6f)
        {
            transform.position = new Vector3(-9.6f, transform.position.y, 0);
        }
        else if (transform.position.x < -9.6f)
        {
            transform.position = new Vector3(9.6f, transform.position.y, 0);
        }

    }
2

I can only assume the is that you are doing

(_speed * 1.5f) for player one

and

_speed * _speedboost

Player one could be calculating (_speed * 1.5f) before Time.deltaTime
Whereas player two could be calculating _speedboost * Time.deltaTime first and then * _speed

I could be wrong

3

No, they are at the same spped, but what happens is that player one seems to need to aceelerate to get to that speed