How to use SearchHandler with data binding from ViewModel?

[FroggieFrog]

I have a custom implementation (according to the docs) of SearchHandler and want to use it on different pages.
The app follows MVVM and all pages have a ViewModel with the data to search through.

How can I bind an ObservableCollection<Item> from a ViewModel to my SearchHandler?
This would avoid the loading of all necessary data again.

some sample code:

<!-- a sample page -->
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:viewmodels="clr-namespace:App.ViewModels"
             xmlns:models="clr-namespace:App.Models"
             xmlns:local="clr-namespace:App"
             xmlns:search="clr-namespace:App.Search"
             x:Class="App.Pages.ItemListPage"
             x:DataType="viewmodels:ItemListViewModel">
    <Shell.SearchHandler>
        <search:CustomSearchHandler x:DataType="viewmodels:ItemListViewModel"
                                    ShowsResults="true"
                                    ItemTemplate="{StaticResource searchResultTemplate}"
				    ItemsToSearch="{Binding ItemList}" />
    </Shell.SearchHandler>
</ContentPage>

// a custom SearchHandler
public class CustomSearchHandler : SearchHandler
{
    public ObservableCollection<Item> ItemsToSearch { get; set; }

    protected override async void OnQueryChanged(string oldValue, string newValue)
    {
        base.OnQueryChanged(oldValue, newValue);

        if (string.IsNullOrWhiteSpace(newValue))
        {
            ItemsSource = null;
            return;
        }        

        ItemsSource = ItemsToSearch.Where(x => x.Title.Contains(newValue, StringComparison.OrdinalIgnoreCase)).ToList();
    }
}

// a ViewModel
public partial class ItemListViewModel : ObservableObject
{
    // ...
    [ObservableProperty]
    private ObservableCollection<Item> _itemList;
    // ...
}

[Tafoua]

// you may have to create a bindable property or you shall have a no property found error

public static readonly BindableProperty ItemsToSearchProperty;