Using a DispatchQueue to run code asynchronously

I have a program that works as intended. It incorporates 3 view models and each view model has an associated model. Each model reads in a large CSV file into a data frame and performs some manipulation of the data. I create instances of each view model class by creating a @stateobject in the main content view. Before the initial view can be displayed the code in all three models has to run and it takes a little time. To speed things up I thought about running each models code asynchronously with a DispatchQueue and grouping them together with a DispatchGroup that would wait for their completion before running the code to display the initial view. Unfortunately I have been unable to figure out the implementation. I tried creating one view model that called all three models (see code at end) but it does not work. Any ideas on how to proceed will be appreciated.

Here are the state object call outs in the content view
struct ContentView: View {
    @StateObject var vooVM: VOOViewModel = VOOViewModel()
    @StateObject var vfiaxVM: VFIAXViewModel = VFIAXViewModel()
    @StateObject var principalVM: PrincipalViewModel = PrincipalViewModel()
    @State private var selectedItemId: Int?
    var body: some View {

Here is a snippet of the begining of one of the view models.
class VOOViewModel: ObservableObject {
    @Published private var vooModel: VOOModel = VOOModel()
    var timeSeriesDailyDF1: DataFrame {
        return vooModel.vooDF.0

Here is a snippet of one of the models
struct VOOModel {
    var vooDF = GetDF(fileName: "FormattedVOO")

Here is the view model I created which calls all three models but it fails with: invalid redeclaration of que().
class ViewModel: ObservableObject {
    let que =
    let group = DispatchGroup()
    que.async(group: group) {
        @Published private var vooModel: VOOModel = VOOModel()
    que.async (group: group) {
        @Published private var vfiaxModel: VFIAXModel = VFIAXModel()
    que.async (group: group) {
        @Published private var principalModel: PrincipalModel = PrincipalModel()