One more thing if you installed on ZFS: /var/snap is a subvolume. Purging snapd wants to remove the /var/snap directory, but it being mounted subvolume, it wil

One more thing if you installed on ZFS: /var/snap is a subvolume. Purging snapd wants to remove the /var/snap directory, but it being mounted subvolume, it will fail. Purging snapd will therefore also fail. Destroy (-r) the /var/snap subvolume before apt purge snapd. Similarly, if using flatpak, create a new subvolume for /var/lib/flatpak before installing the first one. You don't need to snapshot your flatpaks together with the /.