I have found a perfect solution from msdn document. Now you can code like this:

First, create a label and use this code:

            <Label x:Name="MenuLabel" StyleClass="LabelStyle1" Text="RightClickMenu">
                <FlyoutBase.ContextFlyout>
                    <MenuFlyout>
                        <MenuFlyoutItem Text="Back" Command="{Binding BackCommand}" >
                            <MenuFlyoutItem.KeyboardAccelerators>
                                <KeyboardAccelerator Modifiers="None" Key="Left" />
                            </MenuFlyoutItem.KeyboardAccelerators>
                        </MenuFlyoutItem>
                        <MenuFlyoutItem Text="Forward" Command="{Binding ForwardCommand}" >
                            <MenuFlyoutItem.KeyboardAccelerators>
                                <KeyboardAccelerator Modifiers="None" Key="Right" />
                            </MenuFlyoutItem.KeyboardAccelerators>
                        </MenuFlyoutItem>
                        <MenuFlyoutItem Text="GoToStart" Command="{Binding GoToStartCommand}" >
                            <MenuFlyoutItem.KeyboardAccelerators>
                                <KeyboardAccelerator Modifiers="None" Key="Up" />
                            </MenuFlyoutItem.KeyboardAccelerators>
                        </MenuFlyoutItem>
                        <MenuFlyoutItem Text="GoToEnd" Command="{Binding GoToEndCommand}" >
                            <MenuFlyoutItem.KeyboardAccelerators>
                                <KeyboardAccelerator Modifiers="None" Key="Down" />
                            </MenuFlyoutItem.KeyboardAccelerators>
                        </MenuFlyoutItem>
                    </MenuFlyout>
                </FlyoutBase.ContextFlyout>
            </Label>

Second, hide the label. Now , You have keyboard event. It is so simple.

Attention!! the method is only available in .net core 8.

Good luck.

if you want to know more, you would read

https://learn.microsoft.com/en-us/dotnet/maui/user-interface/keyboard-accelerators?view=net-maui-8.0

thank you!