Removing Selection Indicator from CollectionView on Windows in .net maui

Please try SelectionMode = "None" and handling selection manually first.

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:YourNamespace"
             x:Class="YourNamespace.MainPage">
    <ContentPage.BindingContext>
        <local:MyViewModel />
    </ContentPage.BindingContext>
    <CollectionView ItemsSource="{Binding Items}"
                    SelectionMode="None" 
                    Margin="20">
        <CollectionView.ItemTemplate>
            <DataTemplate x:DataType="local:MyItem">
                <Grid Padding="10"
                      BackgroundColor="{Binding BackgroundColor}">
                    <Label Text="{Binding Name}" 
                           VerticalOptions="Center" />
                    <Grid.GestureRecognizers>
                        <TapGestureRecognizer 
                            Command="{Binding Source={RelativeSource AncestorType={x:Type local:MyViewModel}}, Path=ToggleSelectionCommand}"
                            CommandParameter="{Binding .}" />
                    </Grid.GestureRecognizers>
                </Grid>
            </DataTemplate>
        </CollectionView.ItemTemplate>
    </CollectionView>
</ContentPage>

If you want more control over this, you may need to implement your own custom CollectionView handler.