I cloned a Debian VM and all I had to do was copy the vdisk and reinstall grub, filesystem included an efi partition 512MB and LVM2 vgroup with / /var /tmp /home.
The main trick was getting past the yellow efi CLI.
# Copy vdisk
ssh unraid
cd /mnt/disk1/domains
cp -rp DebianTemplate/vdisk1.img NewMachineName
# Double check the owner and permissions are the same as other VM's
ls -ld *; ls -l */vdisk1.img
# Use chown and chmod if owner and permissions don't match
# Create a new VM called NewMachineName but leave startup ISO blank
# If use vdisk location as automatic and the machine name is the same as the directory you copied to NewMachineName in this case
# it will automagically show you the vdisk location correctly otherwise manually adjust the vdisk location.
# Boot and you get the yellow efi shell menu
# Type exit (if I recall correctly) to get another graphical boot system test menu it looks like a UEFI/BIOS
# The last entry I think where you navigate the file system
# Go to to EFI or efi
# then debian
# then select grub and it boots into grub
# login as root user, open a terminal, and run
update-grub
# check where is the efi filesystem with
lsblk
# reinstall the grub to the efi paritition created on the original install in my case /devvda1
grub-install /dev/vda1
.. and it boots
I would guess you could copy and Windows vdisk the same way and navigate the efi CLI to boot to windows and do a boot repair.