public class Venue
        {    
            public List<string> emails { get; set; }     
        }

        public class Event
        {
            public object category { get; set; }
            public string id { get; set; }
            public string name { get; set; } 
            public string description { get; set; }    
            public Venue venue { get; set; }
        }
  public class Place
        {
            public string id { get; set; }
            public string name { get; set; }
            public Location location { get; set; }
        }

 public class Location
        {
           
            public string street { get; set; }
            
        }

  foreach (Model.Event Event in Events.OrderBy(a => a.startTime.Date))
            {

 ReadyEvents.Add(new Model.ReadyFullEvent {
   Title = Event.name,

  Text = (Event.description ?? "").ToString(), //тут все ок, с строкой работает

Email = (Event.venue.emails[0] ?? string.Empty).ToString(), //а вот с этим списком - исключение - "ссылка не указывает на значение"

Street = (Event.place.location.street ?? "").ToString(), //аналогично и тут
 });

}
               

(Event?.venue?.emails[0] ?? string.Empty).ToString()
(Event?.place?.location.street ?? "").ToString()

(Event?.venue?.emails[0] ?? string.Empty).ToString()

(Event?.venue?.emails?[0] ?? string.Empty).ToString()