According to the Qlik Cloud Platform document, Qlik leverages our cloud providers for backups to maintain copies of content for 30 days.
Can I restore one of those backups?
No, those backups cannot be restored. They are kept for disaster recovery purposes (see Disaster recovery/backup and recovery) and encompass entire regions.
It's therefore not possible to recover a tenant's previous stage.
It's the tenant admin's responsibility to make sure that copies of the content are regularly backed up on any platform of choice for easy restoration. See Qlik Cloud Administration: Backup Responsibilities for details.