Google Cloud accidentally wiped an Australian super[annuation] (pension) fund's entire cloud deployment earlier this year. I think that if you really want durable backups, they have to be reducible to object storage and put in someone else's cloud.
From their joint statement [0]:
> when the deletion of UniSuper’s Private Cloud subscription occurred, it caused deletion across both of these geographies.
> an extensive recovery of our Private Cloud which includes hundreds of virtual machines, databases and applications.
> UniSuper had backups in place with an additional service provider. These backups have minimised data loss
Strangely enough on this last point a Google blog post [1] says:
> This incident did not impact: The customer’s data backups stored in Google Cloud Storage (GCS) in the same region.
[0] https://www.unisuper.com.au/about-us/media-centre/2024/a-joi...
[1] https://cloud.google.com/blog/products/infrastructure/detail...