MAUI : await Shell.Current.GoToAsync take too much time

I am developing a project using MAUI and I have some issues with the shell navigation.
There is the line in my code :

await Shell.Current.GoToAsync(nameof(DetailMenuPage));

This execution time code is very long . I have some business code before it takes no time compared to the navigation. Also, I have other business which is executed during the navigation (in a command for the Appearing event) and takes no time too.
There is the full code before and during the navigation :

public async Task SelectItem(object selectedCategorie)
{
   if (selectedCategorie is CategorieMenu)
   {
      var cSelectedCategorie = selectedCategorie as CategorieMenu;
      var sousCategorie = await _serviceToSousCategorieMenu.GetByCategorieMenuId(new List<int> { cSelectedCategorie.CategorieMenuId });
      StaticContext.CategorieMenuName = cSelectedCategorie.Name;
      StaticContext.SousCategorieMenu = sousCategorie;
      var watch = new System.Diagnostics.Stopwatch();
      watch.Start();
      await Shell.Current.GoToAsync(nameof(DetailMenuPage));
      watch.Stop();
      Console.WriteLine($"Execution Time: {watch.ElapsedMilliseconds} ms");
   }
}

Here the watch.ElapsedMilliseconds takes 4692 ms.

[RelayCommand]
public async Task Load()
{
   var watch = new System.Diagnostics.Stopwatch();
   watch.Start();
   var allItem = await _serviceMenuItem.GetBySousCategorieMenuId(StaticContext.SousCategorieMenu.Select(sc => sc.SousCategorieMenuId).ToList());
   if (allItem != null && allItem.Count > 0)
   {
      var groupedItem = allItem.GroupBy(u => u.SousCategorieMenuId).Select(grp => grp.ToList()).ToList();
      Title = StaticContext.CategorieMenuName;
      groupedItem.ForEach(c =>
      {
          Items.Add(new CategorieGroup
          (
             StaticContext.SousCategorieMenu.FirstOrDefault(sc => sc.SousCategorieMenuId == c.FirstOrDefault().SousCategorieMenuId).Name,
                    c
          ));
      });
   }
   watch.Stop();
   Console.WriteLine($"Execution Time: {watch.ElapsedMilliseconds} ms");
}

Here the watch.ElapsedMilliseconds takes 168 ms.

Did I miss something or did you have any tips ?

EDIT :

There the constructor of DetailMenuPage :

public DetailMenuPage(DetailMenuPageViewModel vm)
{
	InitializeComponent();
	BindingContext = vm;
}

The content of DetailMenuPage :

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="Byron.Page.DetailMenuPage"
             xmlns:ViewModels="clr-namespace:Byron.ViewModel"
             xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
             x:DataType="ViewModels:DetailMenuPageViewModel"
             xmlns:Models ="clr-namespace:Byron.Model.DTO"
             xmlns:Converter="clr-namespace:Byron.Helper.Converter"
             xmlns:IHM ="clr-namespace:Byron.Model.IHM"
             Routing.Route="DetailPage"
             Title="{Binding Title}">
    <ContentPage.Behaviors>
        <toolkit:EventToCommandBehavior EventName="Appearing" Command="{Binding LoadCommand}" />
    </ContentPage.Behaviors>
    <ContentPage.Resources>
        <Converter:DoubleToStringConverter x:Key="doubleToStringConverter" />
    </ContentPage.Resources>
    
    
    <ScrollView>
        <StackLayout>
            <CollectionView ItemsSource="{Binding Items}" IsGrouped="True" >
                <CollectionView.GroupHeaderTemplate>
                    <DataTemplate x:DataType="IHM:CategorieGroup">
                        <StackLayout HorizontalOptions="FillAndExpand">
                            <Label Text="{Binding GroupTitle}" Style="{StaticResource TitleGroupMenu}"/>
                        </StackLayout>
                    </DataTemplate>
                </CollectionView.GroupHeaderTemplate>
                <CollectionView.ItemTemplate>
                    <DataTemplate x:DataType="Models:MenuItem">
                        <Frame CornerRadius="10" Margin="10" BorderColor="{AppThemeBinding Light=Black, Dark=White}" BackgroundColor="Transparent">
                            <StackLayout Orientation="Vertical" HorizontalOptions="FillAndExpand" VerticalOptions="CenterAndExpand">
                                <StackLayout Orientation="Horizontal">
                                    <Label Text="{Binding Name}" Style="{StaticResource ItemMenu}" />
                                    <Label Text="{Binding Prix, Converter={StaticResource doubleToStringConverter}}" HorizontalOptions="EndAndExpand" Style="{StaticResource ItemMenu}"/>
                                </StackLayout>
                                <Rectangle HeightRequest="1" BackgroundColor="Black" Margin="0,0,100,0" />
                                <Label Text="{Binding Description}" VerticalOptions="Center" TextColor="{AppThemeBinding Light=Black, Dark=White}" />
                            </StackLayout>
                        </Frame>
                    </DataTemplate>
                </CollectionView.ItemTemplate>
            </CollectionView>
        </StackLayout>
    </ScrollView>
</ContentPage>

And the constructor of the view model :

 public DetailMenuPageViewModel(Services.SQLite.Interfaces.IServiceMenuItem serviceMenuItem)
 {
     _serviceMenuItem = serviceMenuItem;
 }

 <ScrollView>
        <StackLayout>
            <CollectionView ItemsSource="{Binding Items}" IsGrouped="True" >

Non-vertically restricted visual elements should not be inside other non-vertically restricted containers.

The interesting part is that I usually see combination of two of those above, when people complain about performance. Your code goes way beyond that.

Limit your VisualElements. Be it with requesting height or otherwise.

I think I can safely recommend the edit:

<Grid>
     <CollectionView...

(without having any idea what you are trying to do)

In addition to H.A.H's answer, consider these changes:

1. Do you need ScrollView? CollectionView knows how to scroll. If you eliminate ScrollView, then also remove the StackLayout (or Grid from H.A.H.'s answer).:

<ScrollView>
    <StackLayout>
        <CollectionView

becomes:

<CollectionView

2. Whereever you use StackLayout, change to VerticalStackLayout or HorizontalStackLayout, depending on direction.

3. Use Border instead of Frame. Frame was kept for backwards compatibility with Xamarin, but uses an old rendering approach. The Frame doc recommends using Border instead.

4. Your Load method runs during Appearing event. Don't use Items.Add at that time, when filling the collection. (I think) this triggers layout logic on each Add. Instead, build the collection in a local variable, then assign it to Items:

var items = new ...same-type-as-Items...();
...
items.Add(...);   // Add to local `items` instead of `Items`.
...
// When all items have been added.
Items = items;

5. Consider setting HeightRequest inside <CollectionView.ItemTemplate>. This goes on the outer layout. Except when you have Frame or Border put it on the content of the frame/border: <VerticalStackLayout HeightRequest="99" ...>. Replace "99" with whatever height looks good. Fixed-height items are MUCH faster to lay out.