Disclaimer
Flatpak uses OSTree, like Fedora Atomic Desktops (Silverblue, Kinoite etc) and similar to BTRFS snapshots.
So many files are deduplicated and linked, not actually there
https://gitlab.com/TheEvilSkeleton/flatpak-dedup-checker
50GB without
31GB with deduplication
21,4GB with BTRFS compression
There’s no any magic that could reduce Silverblue size, it is based on the same packages as Workstation. Only the installed subset of packages can differ.
Like gnome-tweaks, if you install it in toolbox, it will pull 300mb of dependencies and once installed it is 900mb. Is it magick or 900mb less? Gparted is also missed in Silverblue and not available as flatpaks. Also some magick or anothe MB’s?
Yes, it’s kinda magic if you are unable to remove them in non-atomic distro.
But gnome-tweaks removed from Workstation wont free you 900mb lol. Other apps need those 900mb dependencies too.