how to parse and fetch this array

I found an example of event management that I would like to use this is my error

type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'Iterable'

initially I have this array

 loadPreviousEvents() {
    mySelectedEvents = {
      "2022-09-13": [
        {"eventDescp": "11", "eventTitle": "111"},
        {"eventDescp": "22", "eventTitle": "22"}
      ],
      "2022-09-30": [
        {"eventDescp": "22", "eventTitle": "22"}
      ],
      "2022-09-20": [
        {"eventTitle": "ss", "eventDescp": "ss"}
      ]
    };
  }

I translate this using mysql this what i try

  Future<List<Event>> getData() async {
            var url = 'xxxxxxx';
            var res = await http.get(Uri.parse(url));
            var mySelectedEvents = json.decode(res.body);
            for (var event in mySelectedEvents) {
              for (var eventInfo in event) {
                print(eventInfo["descript"]);
                print(eventInfo["title"]);
              }
            }
            // print(destinations);
            return mySelectedEvents;
          }