gnome-session という便利なツールがあったのでご紹介します。

$ sudo apt install gnome-session

以下のパッケージが新たにインストールされます:
  apg bolt cheese-common colord colord-data cracklib-runtime cups-pk-helper
  dconf-cli evolution-data-server fonts-cantarell gir1.2-accountsservice-1.0
  gir1.2-atspi-2.0 gir1.2-gck-1 gir1.2-gcr-3 gir1.2-gdesktopenums-3.0
  gir1.2-gdm-1.0 gir1.2-geoclue-2.0 gir1.2-gnomebluetooth-1.0
  gir1.2-gnomedesktop-3.0 gir1.2-gweather-3.0 gir1.2-ibus-1.0 gir1.2-json-1.0
  gir1.2-mutter-2 gir1.2-nm-1.0 gir1.2-nma-1.0 gir1.2-rsvg-2.0
  gir1.2-upowerglib-1.0 gjs gkbd-capplet gnome-accessibility-themes
  gnome-control-center gnome-control-center-data gnome-control-center-faces
  gnome-online-accounts gnome-session gnome-session-bin gnome-session-common
  gnome-settings-daemon gnome-settings-daemon-schemas gnome-shell
  gnome-shell-common gnome-startup-applications gnome-themes-extra
  gnome-themes-extra-data gnome-user-docs gnome-user-guide
  gstreamer1.0-clutter-3.0 gstreamer1.0-x ibus libcanberra-pulse
  libcheese-gtk25 libcheese8 libclutter-gst-3.0-0 libcolord-gtk1
  libebackend-1.2-10 libebook-1.2-19 libecal-1.2-19 libedata-book-1.2-25
  libedata-cal-1.2-28 libgdm1 libgeocode-glib0 libgjs0g libgmime-3.0-0
  libgnome-bluetooth13 libgnomekbd-common libgnomekbd8 libgoa-backend-1.0-1
  libgrilo-0.3-0 libgweather-3-15 libgweather-common libibus-1.0-5
  libmozjs-52-0 libmutter-2-0 libnss-myhostname libtotem-plparser-common
  libtotem-plparser18 libwhoopsie-preferences0 libxcb-res0 mousetweaks mutter
  mutter-common nautilus-data pulseaudio-module-bluetooth
  python3-macaroonbakery python3-nacl python3-protobuf python3-pymacaroons
  python3-rfc3339 python3-tz ubuntu-docs ubuntu-system-service
  ubuntu-wallpapers ubuntu-wallpapers-bionic whoopsie-preferences
  xserver-xorg-legacy xwayland
アップグレード: 0 個、新規インストール: 96 個、削除: 0 個、保留: 0 個。

インストール後、[実行]から「gnome-session-properties」を実行すると設定画面が表示されます。