Xamarin CollectionView event and command issue - xamarin.forms

Question

I work on the front end of our app, configuring the UI. Our app originally had a ListView using Xamarin Community Toolkit's EventToCommandBehavior with custom ViewCells to facilitate the search. We set up custom renderers to change the ViewCell's background color. However, when I moved over to the Mac, we discovered that none of that worked with iOS; the cell background would not change.
At this point, I switched to a CollectionView with a TapGestureRecognizer on the grid using VisualStateManager to change the background color. Since then, I can either get the grid selection to highlight without the command enabling our buttons or the command to fire which enables the buttons, but the grid selection will not highlight. Simply put, I either get the command or the event but have been unable to get them working together. This is also a problem on our store page; the IAP's never highlighted before the purchase confirmation popped up. We have been experiencing this issue from the start and never noticed.
Here is the relevant XAML:
<!--Faction Search Results-->
<Frame Grid.Row="2" Grid.Column="0" Grid.ColumnSpan="6" BackgroundColor="Black" BorderColor="White" CornerRadius="5">
<CollectionView ItemsSource="{Binding FactionItems}"
BackgroundColor="Transparent">
<CollectionView.ItemTemplate>
<DataTemplate>
<Grid x:DataType="Data:Faction" BackgroundColor="Black">
<Grid.GestureRecognizers>
<TapGestureRecognizer
NumberOfTapsRequired="1"
Command="{Binding Source={RelativeSource AncestorType={x:Type local:FactionTopPageViewModel}}, Path=ItemTapped}"
CommandParameter="{Binding .}">
</TapGestureRecognizer>
</Grid.GestureRecognizers>
<Grid.RowDefinitions>
<RowDefinition Height="{markups:OnScreenSize DefaultSize='12', iPod='20', iPhoneSE='20', iPhoneXR='20', iPhoneX='20', iPhone13='25', iPhone7p='25', iPhone11pm='25', iPhone13pm='16',
iPadMini='35', iPad9p7='35', iPad='35', iPadAir='35', iPad11='35', iPad12p9='40', Nexus1='20', NexusR='25', Nexus7R='30', Pixel2R='25', Pixel3R='25', GalaxyS8='25', Nexus6P='25', Pixel3XL='25', PixelC='40'}" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Label Padding="10,5" Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="4" Text="{Binding FactionName}" HorizontalOptions="Start" VerticalTextAlignment="End" FontAttributes="Bold"
FontSize="{markups:OnScreenSize DefaultSize='12', iPod='15', iPhoneSE='15', iPhoneXR='18', iPhoneX='19', iPhone13='19', iPhone7p='19', iPhone11pm='19', iPhone13pm='16',
iPadMini='30', iPad9p7='30', iPad='32', iPadAir='32', iPad11='34', iPad12p9='34', Nexus1='14', NexusR='14', Nexus7R='22', Pixel2R='20', Pixel3R='20', GalaxyS8='20', Nexus6P='18', Pixel3XL='18', PixelC='34'}" />
<Label Padding="0,5" Grid.Row="0" Grid.Column="4" Grid.ColumnSpan="2" Text="{Binding NumberMembersString}" HorizontalOptions="Center" VerticalTextAlignment="End" FontAttributes="Bold"
FontSize="{markups:OnScreenSize DefaultSize='12', iPod='15', iPhoneSE='15', iPhoneXR='18', iPhoneX='19', iPhone13='19', iPhone7p='19', iPhone11pm='19', iPhone13pm='16',
iPadMini='30', iPad9p7='30', iPad='32', iPadAir='32', iPad11='34', iPad12p9='34', Nexus1='14', NexusR='14', Nexus7R='22', Pixel2R='20', Pixel3R='20', GalaxyS8='20', Nexus6P='18', Pixel3XL='18', PixelC='34'}"/>
<VisualStateManager.VisualStateGroups>
<VisualStateGroup Name="CommonStates">
<VisualState Name="Normal"></VisualState>
<VisualState Name="Selected">
<VisualState.Setters>
<Setter Property="BackgroundColor" Value="#ae00ff"/>
</VisualState.Setters>
</VisualState>
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
</Grid>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
Relevant code from the ViewModel:
public Command<Faction> ItemTapped { get; }
public FactionTopPageViewModel()
{
ItemTapped = new Command<Faction>(OnItemSelected);
}
private void OnItemSelected(Faction faction)
{
if (faction == null)
{
SelectedItem = null;
DisableFactionButtons();
return;
}
EnableFactionButtons();
SelectedItem = faction;
}
This results in our buttons enabled at the bottom of the page, but the faction (essentially a team) is not being highlighted in the CollectionView, so the user does not receive confirmation of selecting the proper faction.
If I remove the tapgesture and work through the CollectionView commands setting the SelectionMode="Single", SelectionChangedCommand={Binding IsTapped}, and SelectionChangedCommandParameter={Binding .} then the selected Faction highlights without enabling any buttons. These issues are not platform-specific, like the ListView ViewCell background.
I have been working on this longer than I care to mention, as it seems like I have not wrapped my head around some relatively simple concept. Any help would be greatly appreciated, this issue is holding up the next release of our app.