Listview gets the right number of items but doesn't display the value of item attributes

Question

I am using Visual Studio 2022 to make a WPF application that utilises MVVM. I have an observable collection, I have INotifyPropertyChanged implemented, I am binding everything as correctly as I can and have googled a plenty. I'm convinced I have everything correctly and yet the listview won't access the attributes of the items. The listview reflects the number of items that are in the collection but shows a binding error that says the property Autor was not found on the object Kniha. Please excuse my non-English naming, it is for a project where this is the convention and I don't want to rename them just for the sake of this question.

My ListView in MainWindow.xaml:

<Window x:Class="DBKnihovna.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:DBKnihovna"
        xmlns:converters="clr-namespace:DBKnihovna.ViewModel.ValueConverters"
        xmlns:vm="clr-namespace:DBKnihovna.ViewModel"
        xmlns:v="clr-namespace:DBKnihovna.View"
        xmlns:controls="clr-namespace:DBKnihovna.View.Zalozky"
        mc:Ignorable="d"
        WindowStartupLocation="CenterScreen"
        Title="DBKnihovna" Height="600" Width="800">
    <Window.Resources>
        <converters:MultivalueConverterProCommandy x:Key="commandParamConverter" />
        <vm:MainVM x:Key="MainVM" />
        <DataTemplate DataType="{x:Type vm:MainVM}">
            <v:NeprihlasenyUC />
        </DataTemplate>
        <vm:KnihovnikuvVM x:Key="KnihovnikuvVM" />
        <DataTemplate DataType="{x:Type vm:KnihovnikuvVM}">
            <v:KnihovnikuvUC />
        </DataTemplate>
    </Window.Resources>
    <Grid  DataContext="{StaticResource MainVM}">
      <ListView Name="lvVsechnyKnihy" Grid.Row="0" Grid.Column="0"
                 ItemsSource="{Binding VsechnyKnihy}"
                 SelectedValue="{Binding AktualniKniha, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
                 IsSynchronizedWithCurrentItem="True" SelectedItem="{Binding AktualniKniha}">
          <ListView.View>
             <GridView>
                <GridViewColumn DisplayMemberBinding="{Binding Autor}" Header="Autor"/>
             </GridView>
          </ListView.View>
      </ListView>
    </Grid>

My MainVM:

    public class MainVM : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler? PropertyChanged;

/* ... */

        private ObservableCollection<Kniha> vsechnyKnihy;
        public ObservableCollection<Kniha> VsechnyKnihy
        {
            get { return vsechnyKnihy; }
            set
            {
                vsechnyKnihy = value;
                OnPropertyChanged(nameof(VsechnyKnihy));
            }
        }

        private Kniha aktualniKniha;
        public Kniha? AktualniKniha
        {
            get { return aktualniKniha; }
            set
            {
                aktualniKniha = value;
                OnPropertyChanged(nameof(AktualniKniha));
            }
        }
/* ... */
        private void OnPropertyChanged(string propertyName)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

My class Kniha:

    public class Kniha
    {
        [BsonId]
        [BsonRepresentation(BsonType.ObjectId)]
        public string ID;

        public string Nazev;
        public string Autor;
        public int RokVydani;
        public int PocetStran;
        public int PocetVytisku;
        public byte[] Obrazek;

        public Kniha(string nazev, string autor, int rok, int pocetStran, int pocetVytisku, byte[] obrazek, string id = "")
        {
            ID = id == "" ? new BsonID().Id.ToString() : id;
            Nazev = nazev;
            Autor = autor;
            RokVydani = rok;
            PocetStran = pocetStran;
            PocetVytisku = pocetVytisku;
            Obrazek = obrazek;
        }
    }

Visually the result looks like this: enter image description here I debugged and all the objects in the collection DO have the value assigned.

What do I need to do differently to see the value of Kniha.Autor in the column Autor?