Variable values not available or they lost their value

In my program in the Input method, it can access the variables name but it can’t access its value.
Here the program:
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class GameManager : MonoBehaviour {


    #region variables // Every variable is set in editor 
    [Header("Scripts")]
    public SetSpawner SS;
    public FigureMoves FM;
    

    [Space]
    [Header("Tiles")]
    public GameObject Tiles;
    public GameObject[,] tiles = new GameObject[8,8]; // this is the only variable not set in the editor


    [Space]
    [Header("Variables")]
    public bool whiteturn = true;
    public bool yes = false; 
    #endregion


    public void Start() // Unity calls this Method
    {
        for (int i = 0; i < 8; i++)
        {
            Transform parent = Tiles.transform.GetChild(i);
            for (int j = 0; j < 8; j++)
            {
                tiles[i, j] = parent.GetChild(j).gameObject;
                tiles[i, j].gameObject.GetComponent<Tile>().PosInput(i, j);
            }
        }
        SS.SpawnNormal(); // This doesn't use any variables from here.
        FM.Input(tiles); // this just sends the tiles array so later on FM can use this
        yes = true;
        TileFiguresN(); // method is later shown
    }
    

    public void Input(int i, int j, bool white, int character) // Called from Tile script OnMouseDown()  Tile script shown later.
    { // THE PROBLEM IS HERE!
        string a;
        a = yes.ToString();
        bool b = true;
        if (Tiles == null)
        {
            b = false;
        }
        a = a + b.ToString();
        b = true;
        if (tiles[0,0] == null)
        {
            b = false;
        }
        a = a + b.ToString();
        b = true;
        if (FM == null)
        {
            b = false;
        }
        a = a + b.ToString();
        Debug.Log(a); // The output is FalseFalseFalseFalse
    }

    
    void TileFiguresN() // This doesn't matter I just put it so you can see the variables doesn't get changed.
    {
        for (int i = 0; i < 8; i++)
        {
            for (int j = 0; j < 8; j++)
            {
                bool _white;
                int character = 0;
                if (i == 1 || i == 0)
                {
                    _white = true;
                }
                else
                {
                    _white = false;
                }
                if (i == 1 || i == 6)
                {
                    character = 1;
                }
                if (i == 0 || i == 7)
                {
                    if (j == 0 || j == 7)
                    {
                        character = 2;
                    }
                    if (j == 1 || j == 6)
                    {
                        character = 3;
                    }
                    if (j == 2 || j == 5)
                    {
                        character = 4;
                    }
                    if (j == 3)
                    {
                        character = 5;
                    }
                    if (j == 4)
                    {
                        character = 6;
                    }

                }
                tiles[i, j].GetComponent<Tile>().Input(_white, character);
            }
        }
    } //Set's characters to tiles
}

In the console the output is FalseFalseFalseFalse
So the variables lost their value.
Everything in the Start method and TileFiguresN method is done and correct I’ve checked it multiple times.

The Tile script:

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

public class Tile : MonoBehaviour {

    public GameManager GM;
    public int[] position = new int[2];
    public bool white;
    public int character;
    public Material avalaible;
    public Material original;
    
    public void Start()
    {
        original = gameObject.GetComponent<Renderer>().material;
    }

    public void OnMouseDown() //This is the method that calls the INPUT
    {
        GM.Input(position[0],position[1], white, character);
    }

    public void PosInput(int i, int j)
    {
        position[0] = i;
        position[1] = j;
    }

    public void Input(bool _white, int _character)
    {
        character = _character;
        white = _white;
    }

    public void Color(bool a)
    {
        if (a)
        {

            gameObject.GetComponent<Renderer>().material = avalaible; 
        }
        else
        {
            gameObject.GetComponent<Renderer>().material = original;
        }
    }

    public int ActiveCh()
    {
        return character;
    }
}

I think this is because you are using a field initializer to set your tiles array which you are not editing You can assign it in your Start() method to initialize it.

Since you are not using the editor to set the tiles array, try this:

   public void Start() // Unity calls this Method
   {
      this.tiles = new GameObject[8, 8];
      // ...   rest of startup code here
   }