Maui XAML Spinner displaces fields in my form when it becomes visible

I'm working on a Maui app (non-blazer) and only targeting Android.

I have an ActivityIndicator (Spinner) that I activate and deactivate using binding.

When the Spinner becomes visible it shifts all fields below down to make room for the spinner.

I would think there is a way to make the spinner overlay all fields instead -- like an absolute location in html; but, I've not figured a way to do that.

Here's some of my XAML

<ActivityIndicator 
    x:Name="theSpinner"
    Grid.Row="1"
    Grid.Column="1"
    HorizontalOptions="Center" 
    VerticalOptions="Center"
    IsVisible="{Binding IsBusy}" 
    IsRunning="{Binding IsBusy}" />

How can I make the spinner appear on top of all other fields?