In unity why doesn't my character fall down when going against object?

Question

In unity 3d when I jump and my character is in mid air if I go into an object by pressing a/s/d/w from the right direction the character will stay stuck in the air as long as I hold it , how can I make it so that the character won't stay in mid air if I'm holding a movement button against an object without ruining the current movement system and variables amounts

here's my movement script:

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

public class movement : MonoBehaviour
{
    public Rigidbody rb;
    public float MouseSensitivity;
    public float MoveSpeed;
    public float jumpForce;
    public float fallMultiplayer = 2.0f;
    // Smoothing factors
    public float moveSmoothing = 0.1f;
    public float rotateSmoothing = 0.1f;

    //animator 
    public Animator anim;
    bool isJumping = false;
    //
    private Vector3 targetMoveDirection;
    private Quaternion targetRotation;


    void Start()
    {
        //Cursor.visible = false;
    }

    void Update()
    {
        anim.SetBool("jump",false);
        //Look around
        Quaternion rotationDelta = Quaternion.Euler(new Vector3(0, Input.GetAxis("Mouse X") * MouseSensitivity, 0));
        targetRotation = rb.rotation * rotationDelta;
        rb.MoveRotation(Quaternion.Lerp(rb.rotation, targetRotation, rotateSmoothing));

        //vertical parameter 
        anim.SetFloat("vertical moving", Input.GetAxis("Vertical"));
        anim.SetFloat("horizontal", Input.GetAxis("Horizontal"));
    
        //Move
        targetMoveDirection = transform.forward * Input.GetAxis("Vertical") + transform.right * Input.GetAxis("Horizontal");
        rb.AddForce(targetMoveDirection * MoveSpeed, ForceMode.VelocityChange);
        rb.velocity = Vector3.Lerp(rb.velocity, Vector3.zero, moveSmoothing);

        //Jump
        if (anim.GetCurrentAnimatorStateInfo(0).IsName("Jump"))
        {
            isJumping = true;
        }
        else
        {
            isJumping = false;
        }
        if (Input.GetKeyDown(KeyCode.Space) && Mathf.Abs(rb.velocity.y) < 0.01f && !isJumping)
        {
            anim.SetBool("jump",true);
            rb.AddForce(Vector3.up * jumpForce, ForceMode.VelocityChange);
            rb.AddForce(Physics.gravity, ForceMode.Acceleration);
        }
        
    }

    private void FixedUpdate()
    {
        if (rb.velocity.y < 0)
        {
            rb.velocity += Vector3.up * Physics.gravity.y * fallMultiplayer * Time.deltaTime;
        }
    }
}

Answer 1

If you do not wish to significantly modify the movement code then one possible solution may be to reduce the friction of the walls to 0 since the player character rigid body is most likely experiencing some friction with the walls causing it to stop falling.

Try creating a Physics3D material, set its friction value to zero (or another sufficiently low value), and then make sure to assign this to your walls.