roll back or restore without snapshots

Hello.

Unfortunately, if you don't have a snapshot left and you don't manage past data (such as application code) locally, you can't restore it.
As mentioned in the documentation below, be sure to take a snapshot if you need the data later.
https://docs.aws.amazon.com/lightsail/latest/userguide/delete-an-amazon-lightsail-instance.html

Deleted instances cannot be recovered. Create a snapshot of an instance before deleting if you might need the data in the instance at a later time. For more information, see Create a snapshot of your Linux or Unix instance or Create a snapshot of your Windows Server instance in.