The real issue here is backups vs disaster recovery.
Backups can live on the same network. Backups are there for the day to day things that can go wrong. A server disk is corrupted, a user accidentally deletes a file, those kinds of things.
Disaster recovery is what happens when your primary platform is unavailable.
Your cloud provider getting taken down is a disaster recovery situation. The entire thing is unavailable. At this point you're accepting data loss and starting to spin up in your disaster recovery location.
The fact they were hit by crypto is irrelevant. It could have been an earthquake, flooding, terrorist attack, or anything, but your primary data center was destroyed.
Backups are not meant for that scenario. What you're looking for is disaster recovery.