This is much simpler than you’d expect (provided there are no hardware passthoughs, and there usually isn’t), All you need to do is copy both the Disk and the XML file (Typically in /etc/libvirt/qemu) then
1- edit the following in the XML file
Create a new virtual machine ID
uuidgen
Create new MAC addresses for every network adapter
https://olavmrk.github.io/html-macgen/
Change the path to the disks to point to where you put the new copy of the disks
Thats it, now you need to tell KVM about it so….
2- Tell KVM about the new definition with the define function
virsh define /etc/libvirt/qemu/newxmlfile.xml