In order for the Golden Visa to be issued, the law requires the value of the property to be 250,0000 euros. Now that you have sold a property that is not worth 250,000, euros it may be checked by the vendor's tax office.
What happens if my residence bought for a Greek Golden Visa is damaged?
I recently bought a home in Greece but am worried about if it is significantly damaged, such as by fire, and I don’t have adequate insurance. If I were to lose the home by something like that or some kind of other natural disaster, would I have to buy another residence to maintain my visa?
Your resident permit is safe.
No, you wouldn't have to buy another one since authorities don't check (and don't really mind) if the house you bought actually exists or not.
For the renewal of your resident permit, among the documents required to renew, is that the acquired property remains under the possession and ownership of the applicant certified by the land registry. So there is no need to buy another property for keeping your resident permit. But in any case, an insurance contract for fire and earthquake dangers is really necessary for every property owner and is under low cost.