UI freezes for 2-3 seconds when loading a carouselview - xamarin

Question

I have a carouselview binded to a viewmodel, on the previous page (call it first page) user can select 2 arguments and with the help of those, the next view (call it second page) is generated accordingly. However, I can't wrap my head around why my view won't load asynchronously.
So my problem: When I click the button on the first page the UI would freeze for like a solid 2-3 seconds, and then start load (asynchronously?) and once it's done it's all good.
Also I couldn't really figure out a better way to inherit values from first page to second so if someone has an idea please let me know.
Any help on how can I fix this I would really appreciate.
The viewmodel for second page
public class DataSelectionViewModel : BaseViewModel
{
public ObservableCollection<Items> FilteredData { get; set; }
public UserSelectionViewModel()
{
_dataStore = DependencyService.Get<IDataStore>();
LoadData= new AsyncAwaitBestPractices.MVVM.AsyncCommand(FilterData);
FilteredData = new ObservableRangeCollection<Items>();
}
public async Task FilterData()
{
FilteredData.Clear();
var filtereddata = await _dataStore.SearchData(Hard, Subject).ConfigureAwait(false);
foreach (var data in filtereddata)
{
FilteredData.Add(data);
}
}
}
The carouselview in second page
<ContentPage.BindingContext>
<db:DataSelectionViewModel/>
</ContentPage.BindingContext>
...
<!-- DataTemplate for carouselview has radiobuttons, label and button all in a grid -->
<CarouselView ItemsSource="{Binding FilteredData}">
Second Page c#
public partial class SecondPage : ContentPage
{
public Coll(bool hard, string subject)
{
InitializeComponent();
var vm = (BaseViewModel)BindingContext;
vm.Hard = hard;
vm.Subject = subject;
/* had to set "hard" and "subject" here again, otherwise data won't load */
}
protected override async void OnAppearing()
{
var vm = (DataSelectionViewModel)BindingContext;
base.OnAppearing();
await vm.LoadData.ExecuteAsync().ConfigureAwait(false);
}
}
The first page view containing the button
<Button x:Name="Start" Pressed="ButtonClick"/>
First page c# --> Here I also tried doing it with a command and a pressed at the same time, because I couldn't come up with a way to save variables to second page viewmodel, that's why I use pressed here
private async void ButtonClick(object sender, EventArgs e)
{
var vm = (BaseViewModel)BindingContext;
vm.Hard = HardButtonSelected == Hard;
vm.Subject = vm.Subject.ToLower();
await Navigation.PushAsync(new SecondPage(vm.Hard, vm.Subject));
}
I have tried not using the OnAppearing method to get my data, but then it wouldn't bind to the page and it would not show, if I were to previously fill the ObservableCollection with my data and then load the page although I would love to be able to do this because it would allow me to create a loading popup also.