Install a default installation.
Open a terminal.
su /sbin/usermod -aG sudo peter
logout.
Open a terminal.
sudo apt install flatpak gnome-software-plugin-flatpak
NOTE: The 2nd package is only needed if running gnome.
sudo flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
Click Activities.
Click Gnome software.
Near top right, click on “Restart Now”.
NOTE: This will refresh the software catalog, and will restart Gnome software.
Open Gnome software.
Near top left, click on the magnifying glass icon, which is to search.
Type text editor.
NOTE: This should show the Text Editor is already installed.
Click on this Text Editor package.
Near top right, it should show under the Open button, Debian GNU/Linux, and a small triangle.
Click the small triangle.
NOTE: This should show that there is also a Flathub version available.
Uninstall the older Debian GNU/Linux version, by clicking on the trashcan icon near the top right, next to the Open button.
Install the Flathub version by selecting it.
Remove the ESR version of Firefox.
sudo apt remove firefox-esr
Open Gnome software.
Install Firefox.
NOTE: Checking the package details shows this is provided by Mozilla.
Remove the old version of Libreoffice.
sudo apt remove libreoffice-common libreoffice-core libreoffice-gnome libreoffice-gtk3 libreoffice-help-common libreoffice-help-en-us libreoffice-style-colibre libreoffice-style-elementary