not sure what the element is actually called so open to changes to the question.
I want to change the color of whatever this is called. I've included the code for my DataTemplate as well as my styles for the menu as I assume its something to do with those.
DATA TEMPLATE
<DataTemplate>
<Grid Style="{StaticResource FlyoutItemStyle}" WidthRequest="280" ColumnDefinitions="Auto, *" Padding="0, 10, 0, 10">
<Image Source="{Binding FlyoutIcon}"
Margin="10"
VerticalOptions="Center"
HorizontalOptions="Center"
HeightRequest="38"
WidthRequest="38" />
<Label Grid.Column="1"
Text="{Binding Title}"
FontSize="12"
HorizontalOptions="StartAndExpand"
VerticalOptions="Center"
x:Name="_label">
<Label.Style>
<Style TargetType="Label">
<Setter Property="TextColor" Value="{StaticResource AusDx_Gold}" />
<Style.Triggers>
<DataTrigger TargetType="Label" Binding="{Binding IsEnabled}" Value="False">
<Setter Property="TextColor" Value="{StaticResource AusDx_Blue}" />
</DataTrigger>
</Style.Triggers>
</Style>
</Label.Style>
</Label>
</Grid>
</DataTemplate>
STYLES
<Style x:Key="FlyoutItemStyle" TargetType="Grid">
<Setter Property="VisualStateManager.VisualStateGroups">
<VisualStateGroupList>
<VisualStateGroup x:Name="CommonStates">
<VisualState x:Name="Normal" />
<VisualState x:Name="Selected">
<VisualState.Setters>
<Setter Property="BackgroundColor" Value="LightGray"/>
<Setter TargetName="_label" Property="Label.TextColor" Value="Black" />
</VisualState.Setters>
</VisualState>
</VisualStateGroup>
</VisualStateGroupList>
</Setter>
</Style>
Any help or guidance is greatly appreciated! :)

This select tab can be changed in the maui in windows/App.xaml. You can add this code to Platforms->Windows-> App.xaml file.
For more styles, you can see the WinUI source code CommonStyles.