public class Item
{
    public Color Color { get; set; } = Colors.Red;
}

public class ViewModel : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    public List<Item> List { get; set; } = new();

    public ICommand ButtonPressedCommand { get; set; }

    public ViewModel()
    {
        List.Add(new Item());
        List.Add(new Item());
        List.Add(new Item());

        ButtonPressedCommand = new Command<Item>(ButtonPressed);
    }

    public void ButtonPressed(Item item)
    {
        item.Color = Colors.Green;
        OnPropertyChanged(nameof(List));
    }

    public void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

public class Item
{
    public Color Color { get; set; } = Colors.Red;
}

public class ViewModel : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    public List<Item> List { get; set; } = new();

    public ICommand ButtonPressedCommand { get; set; }

    public ViewModel()
    {
        List.Add(new Item());
        List.Add(new Item());
        List.Add(new Item());

        ButtonPressedCommand = new Command<Item>(ButtonPressed);
    }

    public void ButtonPressed(Item item)
    {
        item.Color = Colors.Green;
        OnPropertyChanged(nameof(List));
    }

    public void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:Test"
             x:Class="Test.MainPage"
             x:DataType="local:ViewModel">

    <ScrollView>
        <VerticalStackLayout
            Spacing="25"
            Padding="30,0"
            VerticalOptions="Center">

            <CollectionView
                ItemsSource="{Binding List}">

                <CollectionView.ItemTemplate>
                    <DataTemplate>
                        <Button
                            x:DataType="local:Item"
                            Text="Press me"
                            BackgroundColor="{Binding Color}"
                            CommandParameter="{Binding .}"
                            Command="{Binding Source={RelativeSource AncestorType={x:Type local:ViewModel}}, Path=ButtonPressedCommand}"/>
                    </DataTemplate>
                </CollectionView.ItemTemplate>
            </CollectionView>

        </VerticalStackLayout>
    </ScrollView>

</ContentPage>

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:Test"
             x:Class="Test.MainPage"
             x:DataType="local:ViewModel">

    <ScrollView>
        <VerticalStackLayout
            Spacing="25"
            Padding="30,0"
            VerticalOptions="Center">

            <CollectionView
                ItemsSource="{Binding List}">

                <CollectionView.ItemTemplate>
                    <DataTemplate>
                        <Button
                            x:DataType="local:Item"
                            Text="Press me"
                            BackgroundColor="{Binding Color}"
                            CommandParameter="{Binding .}"
                            Command="{Binding Source={RelativeSource AncestorType={x:Type local:ViewModel}}, Path=ButtonPressedCommand}"/>
                    </DataTemplate>
                </CollectionView.ItemTemplate>
            </CollectionView>

        </VerticalStackLayout>
    </ScrollView>

</ContentPage>