I’m not sure if you resolved this yourself in the end, but I was experiencing a similar issue with roughly the same setup (Core Data, CloudKit, and SwiftUI): my iOS changes were syncing with CloudKit, but nothing seemed to change on watchOS. I ended up changing the Core Data codegen for my model(s) from “Class Definition” to “Manual/None” in Xcode’s inspector. I then navigated to “Editor → Create NSManagedObject Subclass…” to create the data model classes, resolved build errors, and committed the changes. It’s a shame that the automatically generated class definitions don’t seem to work as expected; I hope this solution works for you!