Best aproach to pass parameters to withConverter method cloud_firestore 2.1.0

Hi I am trying to migrate to cloud_firestore 2.10 and the documentation https://pub.dev/packages/cloud_firestore/changelog says to implement like this:

final modelsRef = FirebaseFirestore
     .instance
     .collection('models')
     .withConverter<Model>(
       fromFirestore: (snapshot, _) => Model.fromJson(snapshot.data()!),
       toFirestore: (model, _) => model.toJson(),
     );

 Future<void> main() async {
   // Writes now take a Model as parameter instead of a Map
   await modelsRef.add(Model());
   final Model model = await modelsRef.doc('123').get().then((s) => s.data());
 }

But I pass parameters to my models in my case instead of only Model.fromJson(snapshot.data()!) I use for example GeneralProductModel.fromMap(snap.data()!, parameter1, parameter2),

What is the best aproach for this? to use a method instead of final modelRef =?

But if I pass a not null parameter to the method and I only require it for example at read and not at write?

Thanks in advance!