Dependent models preview container error

I have a set of cascading dependent models. I want to create a preview container that adds them all to a preview container. I have created a model container which loads a recipe of my choice in sequentialy so the instantiation works. I noticed that everything loads but only 1 RecipeStep will ever be added. No matter how I do it, only one is added (randomly).

What is the best practice for creating a swiftdata preview with dependent models? How can I put them in a struct / class for easy access? I tried making a class that initialized the whole swiftdata object however the preview crashes when using this.

Note: I know one solution is that I could make child to parent fields optional, but I don't want to do that since I need them required.

@Model
class CocktailRecipe {
    @Attribute(.unique) var id: UUID
    @Attribute(.unique) var name: String
    var info: String?
    var menu: CocktailMenu?
    
    @Relationship(deleteRule: .cascade, inverse: \Ingredient.recipe)
    var ingredients: [Ingredient]
    @Relationship(deleteRule: .cascade, inverse: \RecipeSection.recipe)
    var sections: [RecipeSection]
    
    var created_at: Date
    
    init(name: String, info: String? = nil, menu: CocktailMenu? = nil, sections: [RecipeSection] = [], ingredients: [Ingredient] = []) {
        self.name = name
        self.info = info
        self.menu = menu
        
        self.sections = sections
        self.ingredients = ingredients
        
        self.created_at = Date()
        self.id = UUID()
    }
}

@Model
class Ingredient {
    @Attribute(.unique) var id: UUID
    @Attribute(.unique) var name: String
    var quantity: Float?
    var units: IngredientUnitType
    var type: IngredientType
    var recipe: CocktailRecipe
    
    var created_at: Date
    
    init(name: String, quantity: Float? = nil, units: IngredientUnitType, type: IngredientType, recipe: CocktailRecipe) {
        self.name = name
        self.quantity = quantity
        self.units = units
        self.type = type
        self.recipe = recipe
        
        self.created_at = Date()
        self.id = UUID()
    }
}

@Model
class RecipeSection {
    @Attribute(.unique) var id: UUID
    @Attribute(.unique) var title: String?
    @Attribute(.unique) var index: Int
    @Relationship(deleteRule: .cascade, inverse: \RecipeStep.section)
    var steps: [RecipeStep]
    var recipe: CocktailRecipe
    
    var created_at: Date

    
    init(title: String? = nil, recipe: CocktailRecipe, steps: [RecipeStep] = []) {
        self.title = title
        self.recipe = recipe
        self.index = recipe.sections.count + 1
        self.steps = steps
        
        self.created_at = Date()
        self.id = UUID()
    }
}


@Model
class RecipeStep {
    @Attribute(.unique) var id: UUID
    @Attribute(.unique) var instruction: String
    @Attribute(.unique) var index: Int
    var section: RecipeSection
    
    var created_at: Date
    
    init(instruction: String, section: RecipeSection) {
        self.instruction = instruction
        self.section = section
        self.index = section.steps.count + 1
        
        self.created_at = Date()
        self.id = UUID()
    }
}

let cocktailPreviewContainer: ModelContainer = {
    do {
        let container = try ModelContainer(
            for: CocktailMenu.self, CocktailRecipe.self, Ingredient.self, RecipeSection.self, RecipeStep.self, /*Bottle.self, Bar.self, */
            configurations: ModelConfiguration(isStoredInMemoryOnly: true)
        )
        let modelContext = container.mainContext
        
        let spicyMargarita = CocktailRecipe(name: "Spicy Margarita")
        modelContext.insert(spicyMargarita)
        
        
        // Initialize ingredients
        let spicyMargaritaIngredients = [
            Ingredient(name: "Tequila", quantity: 2, units: .ounces, type: .tequila, recipe: spicyMargarita),
            Ingredient(name: "Lime Juice", quantity: 1, units: .ounces, type: .mixer, recipe: spicyMargarita),
            Ingredient(name: "Agave Syrup", quantity: 0.5, units: .ounces, type: .mixer, recipe: spicyMargarita),
//            Ingredient(name: "Jalapeno", quantity: 3, units: .slices, type: .garnish, recipe: spicyMargarita)
        ]
        
        for ingredient in spicyMargaritaIngredients {
            modelContext.insert(ingredient)
        }
        
        try? modelContext.save()
        
        // Initialize sections and steps
        let preparationSection = RecipeSection(title: "title here", recipe: spicyMargarita)
        modelContext.insert(preparationSection)
        
        try? modelContext.save()
        
        let step1 = RecipeStep(instruction: "Muddle the jalapeno slices in the shaker.", section: preparationSection)
        modelContext.insert(step1)
        let step2 = RecipeStep(instruction: "Add tequila, lime juice, and agave syrup to shaker with ice.", section: preparationSection)
        modelContext.insert(step2)
        let step3 = RecipeStep(instruction: "Shake well.", section: preparationSection)
        modelContext.insert(step3)
        let step4 = RecipeStep(instruction: "Strain into a chilled glass.", section: preparationSection)
        modelContext.insert(step4)
        
        return container
    } catch {
        fatalError("Failed to create container")
    }
    
    
}()

    
    var spicyMargarita: CocktailRecipe

    init() {
        
        // Initialize spicyMargarita recipe
        spicyMargarita = CocktailRecipe(name: "Spicy Margarita")
        
        // Initialize ingredients
        let tequila = Ingredient(name: "Tequila", quantity: 2, units: .ounces, type: .tequila, recipe: spicyMargarita)
        let limeJuice = Ingredient(name: "Lime Juice", quantity: 1, units: .ounces, type: .mixer, recipe: spicyMargarita)
        let agaveSyrup = Ingredient(name: "Agave Syrup", quantity: 0.5, units: .ounces, type: .mixer, recipe: spicyMargarita)
        let jalapeno = Ingredient(name: "Jalapeno", quantity: 3, units: .slices, type: .garnish, recipe: spicyMargarita)
        
        // Initialize sections and steps
        let preparationSection = RecipeSection(recipe: spicyMargarita)
        let preparationSteps = [
            RecipeStep(instruction: "Muddle the jalapeno slices in the shaker.", section: preparationSection),
            RecipeStep(instruction: "Add tequila, lime juice, and agave syrup to shaker with ice.", section: preparationSection),
            RecipeStep(instruction: "Shake well.", section: preparationSection),
            RecipeStep(instruction: "Strain into a chilled glass.", section: preparationSection)
        ]

        //  WHEN THE BELOW IS COMMENTED OUT, no errors, but have many missing objects.
        spicyMargarita.ingredients.append(contentsOf: [tequila, limeJuice, agaveSyrup, jalapeno])
        spicyMargarita.sections.append(preparationSection)
        preparationSection.steps.append(contentsOf: preparationSteps)