To see this, in the SDKBrowserMaui application, change PopupStyling.xaml and see that text changes are not reflected in the control.
For example, changing it to:
<Style TargetType="Button" x:Key="cancelButtonStyle"><Setter Property="BackgroundColor" Value="Transparent"/>
<Setter Property="Text" Value="bob"/>
<Setter Property="TextColor" Value="#1188FF"/>
</Style>
Still shows Cancel as the text.