Why is variable not updating with data?

I have the following code in my View Controller that’s part of my user favourites logic:

var favouritesModel = FavouritesModel()
var userFavourites = UserFavourites()

override func viewDidLoad() {
        super.viewDidLoad()
        
        tableView.delegate = self
        tableView.dataSource = self
        
        favouritesModel.delegate = self
        favouritesModel.getFavourites()
    }

override func viewDidAppear(_ animated: Bool) {
        setStarButton()
    }

func setStarButton() {
        
        if currentUser != nil {
            print("userFavourites: \(userFavourites)") // userFavourites has data           
        }
    }

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
        // Get a cell
        let cell = tableView.dequeueReusableCell(withIdentifier: "IngredientCell", for: indexPath) as! IngredientCell
        
        print("userFavourites: \(userFavourites)") // userFavourites is empty

        // Return the cell
        return cell
    }

favouritesModel.getFavourites() is my model for retrieving the userFavourites data from Firestore.

This seems like an issue with scope, but I haven’t been able to figure it out. Why does the userFavourites variable contain data in func setStarButton() but not in func tableView?