SwiftData persistence between devices

Hello, I have a rudimentary list app that I have started, I am trying to establish a persistent sync with the iOS to the watch app. I am using swift data and have plans to use CloudKit too eventually. I made sure to recreate my data models and have them target both projects, but they only physically exist in the iOS folder.

// Models:

import Foundation
import SwiftData

@Model
class GroceryListModel {
    @Attribute(.unique) var id: String
    var title: String
    var createdAt: Date

    @Relationship var items: [GroceryItemModel]


    
    init(id: String, title: String, createdAt: Date, items: [GroceryItemModel]
    ) {
        self.id = id
        self.title = title
        self.createdAt = createdAt
        self.items = items
    }
}

import Foundation
import SwiftData

@Model
class GroceryItemModel {
    @Attribute(.unique) var id: UUID
    var name: String
    var quantity: Int
    
//    @Relationship var groceryList: [GroceryList]

    
    init(id: UUID, name: String, quantity: Int) {
        self.id = id
        self.name = name
        self.quantity = quantity
    }
}

// for iOS, how I create an item:
//
//  AddGroceryListView.swift
//  Kitchen_Sync
//
//

import SwiftUI
import SwiftData

struct AddGroceryListView: View {
    
    // Link to the persisted location
    @Environment(\.modelContext) private var context
    
    // Search & sort data
    @Query(sort: \.id, order: .forward) var allItems: [GroceryItemModel]

    // Props
    @State private var title = ""
    @State private var location = ""

    // Render view
    var body: some View {
        // provide text fields to enter title and location, and a button to add the list
        
        Text("Title: ")
        
        
        
        Button("Save") {
            createList()
        }
    }
    
    
    // Creates persisted item for list
    func createList() {
        let list = GroceryListModel(id: UUID().uuidString, title: "blah", createdAt: .now, items: allItems
        )
        context.insert(list)
        try? context.save()
    }
}


#Preview {
    AddGroceryListView()
}

// for Apple Watch version:
import SwiftUI
import SwiftData

struct GroceryListView: View {

    @Environment(\.modelContext) private var context
    @Query(sort: \.createdAt, order: .forward) var allGroceryLists: [GroceryListModel]


    var body: some View {
        // display list items and provide option to add new items
        Text("Grocery List View")

        ScrollView {
                VStack {
                    ForEach(allGroceryLists) { item in
                        Text("an item")
                }
            }
        }
    }
}


#Preview {
    GroceryListView()
}

// main app level for iOS:

//
//  Kitchen_SyncApp.swift
//  Kitchen_Sync
//
//


import SwiftUI
import SwiftData

@main
struct Kitchen_SyncApp: App {
    var body: some Scene {
    WindowGroup {
        TabView {
            groceryListView
            groceryAddListView
        }
        .modelContainer(for: [
            GroceryListModel.self,
            GroceryItemModel.self
        ])
    }
}
var groceryListView: some View {
    NavigationStack {
        GroceryListView()
            .navigationTitle("List")

    }
    .tabItem { Label("List", systemImage: "list.bullet.indent") }
}

var groceryAddListView: some View {
    NavigationStack {
        AddGroceryListView()
            .navigationTitle("Add")
    }
    .tabItem { Label("Add", systemImage: "plus") }

}
}

//#Preview {
//    Kitchen_SyncApp()
//}

// Main app for watch:
//
//  Kitchen_SyncApp.swift
//  Kitchen_Sync Watch App
//
//

import SwiftUI
import SwiftData

@main
struct Kitchen_SyncWatchApp: App {
    var body: some Scene {
        WindowGroup {
            TabView {
                groceryListView
            }
            .modelContainer(for: [
                GroceryListModel.self,
                GroceryItemModel.self
            ])
        }
    }

    var groceryListView: some View {
        NavigationView {
            GroceryListView()
                .navigationTitle("List")
        }
        .tabItem { Label("List", systemImage: "list.bullet") }
    }
}