using System;

using System.Collections.Generic;

using System.Linq;

public class Program {

  public static List<string> funWithAnagrams(List<string> text) {

    if (text is null)

      throw new ArgumentNullException(nameof(text));

​

    var unique = new HashSet<string>();

​

    for (int i = 0; i < text.Count; ) // no i++ here

      if (unique.Add(string.Concat(text[i].OrderBy(c => c))))

        i += 1;           // either go to the next word

      else

        text.RemoveAt(i); // or remove current word

​

    text.Sort();

​

    return text;

  } 

  public static void Main() {

    List<string> str = new() {

      "code",

      "doce",

      "ecod",

      "framer",

      "frame",

    };

    var text = funWithAnagrams(str); 

    Console.Write(string.Join(", ", text));  

  }

}