How to fix so that the character in Unity does not fly into "space" when jumping against the wall?

Question

2D

Good afternoon!
I'm self-taught because I don't understand a lot. I compiled a script for a Persian so that it would normally move, but all the time I received new bugs, therefore I collected the script from various sources. Everything seems to be working fine, but when jumping against the wall, the character flies into "space". Played with the ground search diameter values ​​- does not help. I changed the search point from the Persian, it also does not work.
To understand the full script below:

spoiler

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


public class PControler2 : MonoBehaviour{
    [SerializeField]
    private int lives = 5;
    [SerializeField]
    private float speed = 3.0F;
    [SerializeField]
    private float jumpForce = 5.0F;

    private bool isGrounded;
  public Transform groundCheck;
  public float checkRadius;
  public LayerMask whatIsGround;

    new private Rigidbody2D rigidbody;
    private Animator animator;
    private SpriteRenderer sprite;
  private int extraJumps;
  public int extraJumpsValue;

    private void Awake()    {	
        rigidbody = GetComponent<Rigidbody2D>();  
        animator = GetComponent<Animator>();
        sprite = GetComponentInChildren<SpriteRenderer>();
    }
  private void Start()	{
    extraJumps = extraJumpsValue;
    rigidbody = GetComponent<Rigidbody2D>();
  }
    private void FixedUpdate()    {
    isGrounded = Physics2D.OverlapCircle(groundCheck.position, checkRadius, whatIsGround);
        CheckGround();
    }

    private void Update()    {
    if (isGrounded == true)
    {
      extraJumps = extraJumpsValue;
    }
    if (Input.GetButton("Horizontal")) { Run();}
    if (Input.GetButton("Jump")&& extraJumps > 0) { Jump();
      extraJumps --;}
    else if (Input.GetButton("Jump")&& extraJumps == 0 && isGrounded == true)		{
          }
  }
    private void Run()    {
        Vector3 direction = transform.right * Input.GetAxis("Horizontal");

        transform.position = Vector3.MoveTowards(transform.position, transform.position + direction, speed * Time.deltaTime);

        sprite.flipX = direction.x < 0.0F;
    }

    private void Jump()    {
        rigidbody.AddForce(transform.up * jumpForce, ForceMode2D.Impulse);
    }

    private void CheckGround()    {
        Collider2D[] colliders = Physics2D.OverlapCircleAll(transform.position, 0.6F);

        isGrounded = colliders.Length > 1;
    }
}

Answer 1

The code:
It doesn't work because immediately after that, the CheckGround() function is called, in which the isGrounded variable is overwritten again:

Collider2D[] colliders = Physics2D.OverlapCircleAll(transform.position, 0.6F);
isGrounded = colliders.Length > 1;

Therefore, we will not consider the first line at all, this is a dummy that does nothing, only the processor loads once again. Let's see what happens in the last lines.
You count the number of colliders in a circular area. And if it's greater than 1, then isGrounded will be true.
Apparently, near the wall you also count the wall. So having a wall makes isGrounded = true.
What is the logic here, you know better.
Fix it. :)