Firestore async issue

I'm calling a Firestore query that does come back, but I need to ensure completion before moving on with the rest of the code. So I need a completion handler...but for the life of me I can't seem to code it.

// get user info from db
    func getUser() async {
        self.db.collection("userSetting").getDocuments() { (querySnapshot, err) in
            if let err = err {
                print("Error getting documents: \(err)")
            } else {
                for document in querySnapshot!.documents {
                    let userTrust = document.data()["userTrust"] as! String
                    let userGrade = document.data()["userGrade"] as! String
                    let userDisclaimer = document.data()["userDisclaimer"] as! String
                    
                    var row = [String]()
                    row.append(userTrust)
                    row.append(userGrade)
                    row.append(userDisclaimer)
                    
                    self.userArray.append(row)
                    
                    // set google firebase analytics user info
                    self.userTrustInfo = userTrust
                    self.userGradeInfo = userGrade

                }
            }
            
        }
    }

Called by:

internal func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        
        FirebaseApp.configure()
        db = Firestore.firestore()
        Database.database().isPersistenceEnabled = true

        Task {
            do {
                let userInfo = await getUser()
            }
        } return true }

I used a Task as didFinishLauncingWithOptions is synchronous and not asynchronous

However, the getUser() still isn't completed before didFinishLauncingWithOptions moves on.

I need the data from getUser as the very next step uses the data in the array, and without it I get an 'out of bounds exception' as the array is still empty.

Also tried using dispatch group within the func getUser(). Again with no joy.

Finally tried a completion handler:

func getUser(completion: @escaping (Bool) -> Void) {

        self.db.collection("userSetting").getDocuments() { (querySnapshot, err) in
            if let err = err {
                print("Error getting documents: \(err)")
            } else {

                for document in querySnapshot!.documents {

                    let userTrust = document.data()["userTrust"] as! String
                    let userGrade = document.data()["userGrade"] as! String
                    let userDisclaimer = document.data()["userDisclaimer"] as! String
                    
                    var row = [String]()
                    row.append(userTrust)
                    row.append(userGrade)
                    row.append(userDisclaimer)
                    
                    self.userArray.append(row)
                    
                    // set google firebase analytics user info
                    self.userTrustInfo = userTrust
                    self.userGradeInfo = userGrade
                    
                    completion(true)
                    }
                
                }
            }
        
        }

Nothing works. The getUser call isn't completed before the code moves on. Can someone please help. I've searched multiple times, looked at all linked answers but I can not make this work.I'm clearly missing something easy, please help