Migrating from CoreData


I’ve built a number of iOS applications with non-trivial schemas using CoreData. For my new project I’d like to move to Realm and potentially Realm Cloud.
I need to make a mind shift from CoreData to Realm. I’ve found the query, update of tables and collections quite straight forward. The problem I’m having is how to structure the updates to objects and where the Transaction control is contained.
Still wrestling with the use of ViewModels to store changed view information and passing it to methods on model objects to perform updates or is there a better structure.
Guess what I’m looking for is a non-trivial application architecture example using Realm that strikes a good balance.
Any assistance appreciated.