Обработка ConsoleKey.Backspace

uses System;
begin
  var Name := '';
  while true do
  begin
    var keyInfo := Console.ReadKey(true);
    var key := keyInfo.KeyChar;
    if (key >= 'A') and (key <= 'Z') or (key >= 'a') and (key <= 'z') then
    begin
      Console.Write(key);
      Name += key;
    end
    else
      if char.IsNumber(key) then
        Console.WriteLine(NewLine + '>>> Char can not be a number.')
      else if char.IsPunctuation(key) then
        Console.WriteLine(NewLine + '>>> Char can not be a punctuation char.')
      else if (keyInfo.Key = ConsoleKey.Backspace) and (Name.Length > 0) then
      begin
        Name := Name.Remove(Pred(Name.Length), 1);
        Console.SetCursorPosition(Console.CursorLeft - 1, Console.CursorTop);
        Console.Write(' ');
      end
      else if keyInfo.Key = ConsoleKey.Enter then
        break;
  end;
  Console.WriteLine(NewLine + 'Your name is {0}.', Name);
end.

if (key >= 'A') and (key <= 'Z') or (key >= 'a') and (key <= 'z')

if  key in['A'..'Z', 'a'.. 'z']