Letter errors statistic

using System;
using System.Linq;

namespace Trening_letter
{
    internal class Program
    {
        static void Main(string[] args)
        {
            string text;
            string errorLetters = "";
            char letter;
            int letterIsEntered = 0;
            bool IsFalseEntered = false;

            bool isOpen = true;
            bool notIsAllEntered = true;

            while (isOpen)
            {
                Console.Write("Вставьте скопированный текст: ");
                text = Console.ReadLine(); //съешь же еще этих мягких французских булок да выпей чаю

                while (notIsAllEntered)
                {
                    Console.Clear();

                    for (int i = 0; i < letterIsEntered; i++)
                    {
                        TrueColor(text[i]);
                    }

                    if (IsFalseEntered)
                    {
                        ErrorColor(text[letterIsEntered]);

                        for (int i = letterIsEntered + 1; i < text.Length; i++)
                        {
                            Console.Write(text[i]);
                        }
                    }
                    else
                    {
                        for (int i = letterIsEntered; i < text.Length; i++)
                        {
                            Console.Write(text[i]);
                        }
                    }

                    letter = Console.ReadKey().KeyChar;

                    if (letter == text[letterIsEntered])
                    {
                        letterIsEntered++;
                        IsFalseEntered = false;
                    }
                    else if(IsFalseEntered == false)
                    {
                        IsFalseEntered = true;
                        errorLetters += text[letterIsEntered];
                    }

                    if (letterIsEntered == text.Length)
                    {
                        notIsAllEntered = false;
                        isOpen = false;
                    }
                }

                Console.WriteLine($"\nОшибки: {errorLetters}");

                Dictionary<char, int> map = new();

                foreach (char c in errorLetters)
                {
                    if (map.ContainsKey(c))
                        map[c]++;
                    else
                        map[c] = 1;
                }

                foreach (var pair in map)
                {
                    Console.WriteLine($"{pair.Key} = {pair.Value}");
                }
            }

            static void ErrorColor(char letter)
            {
                Console.ForegroundColor = ConsoleColor.Red;
                Console.Write(letter);
                Console.ForegroundColor = ConsoleColor.White;
            }

            static void TrueColor(char letter)
            {
                Console.ForegroundColor = ConsoleColor.Green;
                Console.Write(letter);
                Console.ForegroundColor = ConsoleColor.White;
            }
        }
    }
}