crouch script problem

So I'm Trying to make my player crouch, this is the script:

1. using System.Collections; using System.Collections.Generic; using UnityEngine;

   public class PlayerMovement : MonoBehaviour { public ParticleSystem dust; private bool isCrouching; [SerializeField] private float speed; [SerializeField] private LayerMask groundLayer; private Rigidbody2D rb; private Animator anim; private BoxCollider2D boxCollider; private int horizontalInput;

     private void Awake()
        {
            //Grab references for rigidbody and animator from object
            rb = GetComponent<Rigidbody2D>();
            anim = GetComponent<Animator>();
            boxCollider = GetComponent<BoxCollider2D>();
        }
    
        private void Update()
        {
            float horizontalInput = Input.GetAxis("Horizontal");
            rb.velocity = new Vector2(horizontalInput * speed,
    rb.velocity.y);
            //flip player when moving left-right
            CreateDust();
            if (horizontalInput > 0.06f)
                transform.localScale = new Vector3(8, 8, 1);
            else if (horizontalInput < -0.06f)
                transform.localScale = new Vector3(-8, 8, 1);
    
            if (Input.GetKey(KeyCode.Space) &&
    isGrounded())
                Jump();
    
    
            if (Input.GetKeyDown(KeyCode.S))
            {
                boxCollider.enabled = false;
                boxCollider.size = new Vector3(2, 2, 1);
                anim.SetBool("Crouch", true);
            }
            else if (Input.GetKeyUp(KeyCode.S))
            {
                boxCollider.enabled = true;
                anim.SetBool("Crouch", false);
            }
    
    
            //Set animator parameters
            anim.SetBool("run", horizontalInput != 0);
            anim.SetBool("grounded", isGrounded());
        }
    
        private void Jump()
        {
            rb.velocity = new Vector2(rb.velocity.x, speed);
            anim.SetTrigger("jump");
        }
    
        private bool isGrounded()
        {
            RaycastHit2D raycastHit = Physics2D.BoxCast(boxCollider.bounds.center,
    boxCollider.bounds.size, 0,
    Vector2.down, 0.1f, groundLayer);
            return raycastHit.collider != null;
        }
    
        public bool canAttack()
        {
            return horizontalInput == 0 && isGrounded();
        }
    
        public bool canKick()
        {
            return horizontalInput == 0 && isGrounded();
        }
    
        void CreateDust()
        {
            dust.Play();
        } }
   
   

and the box colliders weren't keeping my character from falling through the ground, and I don't understand how to implement it.