❔ getting all methods with an attribute in an optimized way

[Command]
    public void MyCommandMethod()
    {
        // do something!
    }

Assembly[] assemblies = AppDomain.CurrentDomain.GetAssemblies();
            foreach (Assembly assembly in assemblies) 
            {
                foreach (Type type in assembly.GetTypes())
                {
                    foreach (MethodInfo method in type.GetMethods(
                        BindingFlags.Public |
                        BindingFlags.NonPublic |
                        BindingFlags.Instance |
                        BindingFlags.Static))
                    {
                        CommandAttribute command = method.GetCustomAttribute<CommandAttribute>();
                        if (command != null)
                        {
                            string key = command.Name == string.Empty ? method.Name : command.Name;
                            if (!_availableCommands.ContainsKey(key))
                            {
                                _availableCommands.Add(key, method);
                            }
                            else
                            {
                                WriteLine($"command with name '{key}' has already been found!", Color.red);
                            }                            
                        }
                    }
                }
            }