How to dynamically adjust positioning of a VerticalStackLayout inside a Grid? - xaml

Question

I'm creating an app using MAUI and I'm trying to make it so an ImageButton and SearchBar nested in a VerticalStackLayout move positioning based on the dynamically created CollectionView.
This is the code for the UI:
<Grid>
<FlexLayout VerticalOptions="Center" HorizontalOptions="Center">
<StackLayout>
<CollectionView x:Name="taskList">
<CollectionView.ItemTemplate>
<DataTemplate x:DataType="models:Task">
<VerticalStackLayout Margin="15">
<Entry Text="{Binding name}" IsReadOnly="True" />
<Entry Text="{Binding departmentsString}" IsReadOnly="True"/>
<HorizontalStackLayout>
<Entry Text="{Binding status}" IsReadOnly="True"/>
<Entry Text="{Binding deadline}" IsReadOnly="True" />
<Entry Text="{Binding author.fullName}" IsReadOnly="True"/>
</HorizontalStackLayout>
<Entry Text="{Binding description}" IsReadOnly="True" />
</VerticalStackLayout>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
</StackLayout>
<VerticalStackLayout Margin="15">
<Entry Placeholder="Name" x:Name="nameTxt"/>
<Entry Placeholder="Department" x:Name="departTxt"/>
<HorizontalStackLayout>
<inputs:SfComboBox x:Name="statusTxt" Placeholder="Status" BackgroundColor="Black" TextColor="Green" DropDownIconColor="Green"/>
<Entry Placeholder="deadline" x:Name="deadlineTxt"/>
<Entry Placeholder="Author" x:Name="authorTxt"/>
</HorizontalStackLayout>
<Entry Placeholder="Description" x:Name="descTxt"/>
</VerticalStackLayout>
</FlexLayout>
<VerticalStackLayout VerticalOptions="Center" >
<SearchBar Placeholder="Search" x:Name="searchBar" TextChanged="searchBar_TextChanged" MaxLength="30" MaximumWidthRequest="200"/>
<ImageButton Aspect="AspectFill" x:Name="addBtn" Source="plus.png" BackgroundColor="Black" Clicked="addBtn_Clicked" HeightRequest="64" WidthRequest="64"/>
</VerticalStackLayout>
</Grid>
I have tried every different type of Layout but nothing works.
What should I do?