858TB of data over 8 years.
In fact, their G-Drive is designed as a high-capacity, low-performance storage system, and they have regulatory constraints that require exclusive storage on this platform to prevent data leaks.

In short, for all official documents that have gone through formal approval processes, there is hope of recovery via their OnNara system (another government system that stores final reports), but for everything else (drafts, work-in-progress files, internal notes, etc.), it's dead as a doornail...