One idea: build a DR system and turn it off. Ideally it would be cloneable, but even without that ability, one could test it every few months to make sure it bo

One idea: build a DR system and turn it off. Ideally it would be cloneable, but even without that ability, one could test it every few months to make sure it boots adequately quickly and then turn it back off. The attack surface of a bunch of computers or instances that are powered down is pretty low.