Hmmm... sure, I'll try that. But what about the Flatpak stuff? I'ts dumped in there, too:

{
  xdg.portal = {
    enable = true; # Needs to be enabled for Flatpak to work

    # wlr.enable = true;

    configPackages = with pkgs; [ kdePackages.xdg-desktop-portal-kde ];
    xdgOpenUsePortal = true;

    extraPortals = with pkgs; [
      # xdg-desktop-portal-wlr
      xdg-desktop-portal-gtk
    ];
  };

  services.flatpak = { enable = true; };

  # Add Flathub repository if it does not already exist
  systemd.services.flatpak-repo = {
    wantedBy = [ "multi-user.target" ];
    path = [ pkgs.flatpak ];

    script = ''
      flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
    '';
  };

  # System-wide Flatpak installation
  environment.systemPackages = with pkgs; [
    flatpak
    xdg-desktop-portal
  ];
}

25.05.20250508.dda3dcd (Warbler)

plasmashell 6.3.5
QThreadStorage: entry 8 destroyed before end of thread 0x288b1de0
QThreadStorage: entry 2 destroyed before end of thread 0x288b1de0
QThreadStorage: entry 1 destroyed before end of thread 0x288b1de0