.NET Maui CollectionView, como exibir o valor somente se o valor existir

Você precisará de um conversor que converta strings vazias ou nulas em booleanos e, em seguida, precisará atribuí-lo à visibilidade do seu item para que algo como o abaixo funcione,

/// <summary>
/// Inherit this for one-way converters to avoid unnecessary extra methods in each converter
/// </summary>
public abstract class BaseOneWayValueConverter : IValueConverter
{
    public abstract object Convert(object value, Type targetType, object parameter, CultureInfo culture);

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotSupportedException($"{GetType().Name} is a one-way converter");
    }
}

public class StringIsNullToBoolConverter : BaseOneWayValueConverter
{
    public override object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return value is not string text || !string.IsNullOrWhiteSpace(text);
    }
}

E então use-o em seu Label conforme mostrado abaixo:

<ContentPage
.
.
.
.
xmlns:converters=*converter-namepsace-here* 
>
<ContentPage.Resources>
   <StringIsNullToBoolConverter x:Key="StringIsNullToBoolConverter"/>
</ContentPage.Resources>

Em seguida, use-o em seus respectivos rótulos:

<Label Text="{Binding Name}" IsVisible="{Binding Name,Converter={StaticResource StringIsNullToBoolConverter}}"/>

Aqui está uma maneira de fazer isso. Primeiro fazemos o Model que é responsivo usando o INotifyPropertyChangede a PropertyChangedEventHandler, aqui também colocamos o booleano para usar se vamos apresentar a linha ou não.

public class Person : INotifyPropertyChanged
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string FavoriteMovie { get; set; }
    public string FavoriteBook { get; set; }

    public string DisplayName => FirstName + " " + LastName;

    public bool HasFavoriteMovie => !string.IsNullOrEmpty(FavoriteMovie);
    public bool HasFavoriteBook => !string.IsNullOrEmpty(FavoriteBook);

    public event PropertyChangedEventHandler PropertyChanged;
}

O código xaml para imitar o layout da sua imagem. No rótulo/grade vinculamos IsVisibleao valor booleano do modelo.

<ContentPage.Resources>
    <Style x:Key="LabelStyle" TargetType="Label">
        <Setter Property="TextColor" Value="{StaticResource Blue100Accent}" />
        <Setter Property="FontSize" Value="18" />
        <Setter Property="LineHeight" Value="1.2" />
    </Style>
    <Style x:Key="TitleLabelStyle" TargetType="Label">
        <Setter Property="TextColor" Value="{StaticResource Primary}" />
        <Setter Property="FontSize" Value="28" />
        <Setter Property="TextTransform" Value="Uppercase" />
        <Setter Property="FontAttributes" Value="Bold" />
        <Setter Property="HorizontalOptions" Value="Center" />
        <Setter Property="LineHeight" Value="1.2" />
    </Style>
    <DataTemplate x:Key="PeopleTemplate">
        <Border
            Margin="20,10,10,10"
            BackgroundColor="{StaticResource LightBackgroundColor}"
            Stroke="Gray"
            StrokeThickness="2">
            <Border.StrokeShape>
                <RoundRectangle CornerRadius="10" />
            </Border.StrokeShape>
            <Border.GestureRecognizers>
                <TapGestureRecognizer Command="{Binding Source={RelativeSource AncestorType={x:Type viewmodels:PeopleViewModel}}, Path=PersonClickedCommand}" CommandParameter="{Binding .}" />
            </Border.GestureRecognizers>
            <Grid Padding="50,10,10,10">
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                </Grid.RowDefinitions>
                <Label
                    Grid.Row="0"
                    Style="{StaticResource LabelStyle}"
                    Text="{Binding DisplayName}" />
                <Label
                    Grid.Row="1"
                    IsVisible="{Binding HasFavoriteMovie}"
                    Style="{StaticResource LabelStyle}"
                    Text="{Binding FavoriteMovie}" />
                <Label
                    Grid.Row="2"
                    IsVisible="{Binding HasFavoriteBook}"
                    Style="{StaticResource LabelStyle}"
                    Text="{Binding FavoriteBook}" />
            </Grid>
        </Border>
    </DataTemplate>
</ContentPage.Resources>
<VerticalStackLayout HorizontalOptions="Center" VerticalOptions="Center">
    <Label Style="{StaticResource TitleLabelStyle}" Text="People" />
    <CollectionView
        x:Name="PeopleCollection"
        ItemSizingStrategy="MeasureFirstItem"
        ItemTemplate="{StaticResource PeopleTemplate}"
        ItemsSource="{Binding People}">
        <CollectionView.ItemsLayout>
            <LinearItemsLayout Orientation="Vertical" />
        </CollectionView.ItemsLayout>
    </CollectionView>
    <Button
        Command="{Binding AddPersonCommand}"
        Text="Add Person"
        WidthRequest="200" />
</VerticalStackLayout>

E finalmente no seu ViewModel você tem

public partial class PeopleViewModel : ObservableObject
{
    public ObservableCollection<Person> People { get; set; }

    public PeopleViewModel()
    {
        People = new ObservableCollection<Person>
        {
            new Person { FirstName = "John", LastName = "Doe", FavoriteMovie = "Inception", FavoriteBook = "1984" },
            new Person { FirstName = "Jane", LastName = "Doe", FavoriteMovie = "Avatar" },
            new Person { FirstName = "Michael", LastName = "Brown" }
        };
    }

    [RelayCommand]
    private async Task PersonClicked(Person person)
    {
        var navigationParameter = new Dictionary<string, object>
            {
                { "Person", person }
            };
        await Shell.Current.GoToAsync($"{nameof(PersonPage)}", navigationParameter);
    }

    [RelayCommand]
    private void AddPerson()
    {
        People.Add(new Person { FirstName = "Emily", LastName = "Smith", FavoriteBook = "To Kill a Mockingbird" });
    }
}

Isto é o que parece. Espero que seja isso que você deseja.