This Is the only way i found to import the image on zfs:
root@pve-test:~# qm importdisk 103 nethsecurity-8-23.05.2-ns.0.0.1-beta1-x86-64-generic-squashfs-combined-efi.img local-zfs
Disk is bootable.
Used this image to launch ns-install to a blank disk.
Both disk, blank and imported, After upgrade result in bootloop.