Have you tried playing with the popup defaults?

.UseMauiCommunityToolkit(static options =>
{
    options.SetPopupDefaults(new DefaultPopupSettings
    {
        CanBeDismissedByTappingOutsideOfPopup = true,
        BackgroundColor = Colors.Orange,
        HorizontalOptions = LayoutOptions.End,
        VerticalOptions = LayoutOptions.Start,
        Margin = 72,
        Padding = 4
    });

    options.SetPopupOptionsDefaults(new DefaultPopupOptionsSettings
    {
        CanBeDismissedByTappingOutsideOfPopup = true,
        OnTappingOutsideOfPopup = async () => await Toast.Make("Popup Dismissed").Show(CancellationToken.None),
        PageOverlayColor = Colors.Orange,
        Shadow = null,
        Shape = null
    });
})