You can do that with NixOS, booting back to an earlier version is literally one click in the boot manager and happens instantly, as the OS is just resetting som

You can do that with NixOS, booting back to an earlier version is literally one click in the boot manager and happens instantly, as the OS is just resetting some symlinks under the hood. For Debian you might need a file system with snapshot support, e.g. apt-btrfs-snapshot is a package that handles it, though I never used that myself.