Seems interesting, thanks!

No, they’re not trying to recover data, they’re trying to copy data to the disk, to store backups, which they should absolutely not do, that disk is not fit as backup storage.

That’s correct for dd but not for clonezilla.
Clonezilla uses partclone, which reads the file system and copies only the data, for any filesystem sorted by partclone.

Source: Many File systems are supported: (1) ext2, ext3, ext4, reiserfs, reiser4, xfs, jfs, btrfs, f2fs and nilfs2 of GNU/Linux, (2) FAT12, FAT16, FAT32, exFAT and NTFS of MS Windows, (3) HFS+ and APFS of Mac OS, (4) UFS of FreeBSD, NetBSD, and OpenBSD, (5) minix of Minix, and (6) VMFS3 and VMFS5 of VMWare ESX. Therefore you can clone GNU/Linux, MS windows, Intel-based Mac OS, FreeBSD, NetBSD, OpenBSD, Minix, VMWare ESX and Chrome OS/Chromium OS, no matter it’s 32-bit (x86) or 64-bit (x86-64) OS. For these file systems, only used blocks in partition are saved and restored by Partclone. For unsupported file system, sector-to-sector copy is done by dd in Clonezilla.

The easiest way to solve this kind of issue on Nixos is to add

environment.systemPackages = with pkgs; [ steam-run ];

to your configuration.nix, rebuild your system and then run the binary with steam-run, like steam-run linuxrulzgame