Flutter - Convert Data from Firebase Snapshot

I'm trying to get data from a Firebase listener & use it as a Model Object but I'm getting Unhandled Exceptions.

The goal is to get the data, make it a list, and display it on a page in my app.

Here is where I use my firebase listen to get the data:

final chatRef = ref.child("ChildInfo").child(key.toString());
    chatRef.onValue.listen(
        (event) async {
            final data = event.snapshot.value as Map<Object?, Object?>;
            final cleanData = Map<String, dynamic>.from(data);

             final List<ABCModel> abc = cleanData.values
                .map(
                  (raw) => ABCModel.fromJson(raw),
                )
                .toList();

But I'm getting this Unhandled Exception:

[VERBOSE-2:ui_dart_state.cc(209)] Unhandled Exception: type 'String' is not a subtype of type 'Map<String, dynamic>'

This is my fromJson:

factory ABCModel.fromJson(Map<String, dynamic> json) => ABCModel(
        id: json['id'] == null ? null : json['id'] as String?,
        name: json['name'] == null ? null : json['name'] as String?,
        description:
            json['description'] == null ? null : json['description'] as String?,
        imageUrl: json['imageUrl'] == null ? null : json['imageUrl'] as String?,
        date: json['date'] == null
            ? null
            : Parser.parseDateTime(json['date']) ?? DateTime.now(),
        blockedUsers: json['blockedUsers'] == null
            ? null
            : (json['blockedUsers'] as List<dynamic>)
                .cast<Map<String, dynamic>>()
                .map((item) => BlockedUsers.fromJson(item))
                .toList(),
      );

Update:

I have recently tried getting my data as:

Map<String, dynamic> data =
                jsonDecode(jsonEncode(event.snapshot.value));

But, when trying to convert this to a list of my model objects I am still getting [VERBOSE-2:ui_dart_state.cc(209)] Unhandled Exception: type 'String' is not a subtype of type 'Map<String, dynamic>' OR [VERBOSE-2:ui_dart_state.cc(209)] Unhandled Exception: type 'List<dynamic>' is not a subtype of type 'Map<String, dynamic>'

I'm using version: firebase_database: ^9.0.0