Changed this: name: doc.data['name'] ?? ''
Into this: name: doc.data()['name'] ?? ''

Firestore's data used to be a property of QueryDocumentSnapshot, but now it is a function, data().
data() is a method now therefore you have to add (), from the source code.
And, as the error message suggests, what you are dealing with is indeed a Map<String, dynamic> Function(), i.e. a function that returns a map.

So, simply add empty parentheses to call the function data:

Map<String, dynamic> data() {
return _CodecUtility.replaceDelegatesWithValueInMap(
_delegate.data(), _firestore);
}

Refer to Firestore Docs: https://github.com/FirebaseExtended/flutterfire/blob/master/packages/cloud_firestore/cloud_firestore/lib/src/document_snapshot.dart#L38