ConvertArray.cs

    public T[] ConvertMultiArrayToSingleArray(T[,] multiArray)
    {
        int x = multiArray.GetLength(0);
        int y = multiArray.GetLength(1);

        T[] singleArray = new T[x * y];

        int index = 0;

        for (int i = 0; i < x; i++)
        {
            for (int j = 0; j < y; j++)
            {
                singleArray[index++] = multiArray[i, j];
            }
        }

        return singleArray;
    }

    public T[,] ConvertSingleArrayToMultiArray(T[] singleArray, Vector2Int size)
    {
        T[,] multiArray = new T[size.x, size.y];

        int index = 0;

        for (int i = 0; i < size.x; i++)
        {
            for (int j = 0; j < size.y; j++)
            {
                multiArray[i, j] = singleArray[index++];
            }
        }

        return multiArray;
    }