Howto debian12
enable flatpak:
sudo apt update && apt sudo -y instal flatpak
configure gnome software flatpak plugin:
sudo -y apt install gnome-software-plugin-flatpak
enable flatpak repo:
flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
more on flatpak commands: