x:Bind in WinUI3 Binding to a datetime-CodePudding

I am trying to bind current DateTime to a textblock object in WinUI3.

<Page
    x:Class="HabitTracker.Screens.HomePage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:HabitTracker.Screens"
    xmlns:sys="using:System"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
    <Grid> 
      <Grid>
        <GridView MaxHeight="500" ItemsSource="{x:Bind Habits}">
          <GridView.HeaderTemplate>
           <DataTemplate>
            <StackPanel Orientation="Horizontal" Spacing="45">
             <TextBlock Text="{x:Bind sys:DateTime.Now}" />
             <TextBlock Text="hello2" />
             <TextBlock Text="hello2" />
             <TextBlock Text="hello2" />
            <TextBlock Text="hello2" />
         </StackPanel>
       </DataTemplate>
    </GridView.HeaderTemplate>

... But my binding doesn't work. I get empty string on the UI while running the application.

I have the following namespace declaration:

xmlns:sys="using:System"

What am I missing?

Note: I also read this doc