Setting padding of button 25% of the screen in .NET MAUI

I want each one of these buttons to take 25% of the screen. I tried different approaches, but I cannot seem to get it working. Can anyone tell me what I am doing wrong?

Launchpage.xaml

<?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:sys="clr-namespace:System;assembly=System.Runtime"
             x:Class="MauiApp1.Views.LaunchPage"
             Title="LaunchPage"
             BindingContext="{x:Reference Name=This}">
    <VerticalStackLayout>
        <VerticalStackLayout.Resources>
            <sys:Double x:Key="quarterScreensize"></sys:Double>
            <Thickness x:Key="buttonPadding" Top="0" Bottom="{Binding quarterScreensize}" Left="0" Right="0"/>
        </VerticalStackLayout.Resources>
        <Button Text="Schematics" Padding="0,0,0,{Binding quarterScreensize}">
        </Button>
        <Button Text="Exercise list"  Padding="{StaticResource buttonPadding}">
        </Button>
        <Button Text="Options"  Padding="{StaticResource buttonPadding}">
        </Button>
        <Button Text="No idea yet"  Padding="{StaticResource buttonPadding}">
        </Button>
    </VerticalStackLayout>
</ContentPage>

Launchpage.xaml.cs

namespace MauiApp1.Views;
    
public partial class LaunchPage : ContentPage
{
    public double quarterScreensize = DeviceDisplay.MainDisplayInfo.Height / 4;
    public LaunchPage()
    {
        InitializeComponent();
    }
}

You cannot set heights of View elements in percentages in MAUI. What you could do instead, however, is replace the <VerticalStackLayout> with a <Grid> and specify four equally sized rows, like this for example:

<?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:sys="clr-namespace:System;assembly=System.Runtime"
             x:Class="MauiApp1.Views.LaunchPage"
             Title="LaunchPage"
             BindingContext="{x:Reference Name=This}">
    <Grid
        VerticalOptions="Fill"
        RowDefinitions="*,*,*,*">
        <Button Text="Schematics"
            Grid.Row="0" />
        <Button Text="Exercise list"
            Grid.Row="1" />
        <Button Text="Options"
            Grid Row="2" />
        <Button Text="No idea yet"
            Grid.Row="3" />
    </Grid>
</ContentPage>

You also don't need to calculate anything in the code-behind with this approach, so you can remove the quarterScreenSize:

namespace MauiApp1.Views;
    
public partial class LaunchPage : ContentPage
{
    public LaunchPage()
    {
        InitializeComponent();
    }
}