I am trying to make a molti level 2D game in unity, the problem shows up when u load the scene with a level, then u go to the main menu or complete the level and return to the map, and try to restart the same fisrt level. It also occours with the other levels, when i exit the scene of the first level all the codes inside it stop working and i cant move no more.
I use a button with this code for returning to the main menù from the level pause

public void OnBack() { SceneManager.LoadScene("Menu"); }

And i use this code for loading levels:

public void OnLvl1() { SceneManager.LoadScene("Lvl1"); }

The main problem is that the code of the player stops working and it stop moving and attacking, but i can continue to crouch.

private void OnMove(InputValue value )
{
        movement = value.Get<Vector2>();
}

private void OnCrouch()
{
    if( !crouch )
    {
        animator.SetFloat("crouch", 1);
    }
    else
    {
        animator.SetFloat("crouch", 0);
    }
    crouch = !crouch;
}

public void Update(){
    if (!crouch && (movement.x != 0 || movement.y != 0) && !attacking && !performing)
    {
        transform.position = new Vector3(transform.position.x + movement.x * speed * 
    Time.deltaTime, transform.position.y + movement.y * speed * Time.deltaTime, 
    transform.position.z);
        animator.SetFloat("speed", movement.x != 0? 1 :movement.y != 0? 1 :0);
    }
    else
    {
        animator.SetFloat("speed", 0);
    }
}

for the input system i use the player input manager.