Google Drive cannot be trusted with Scrivener projects. It is known to cause data corruption. You can safely use it with ZIP files, but please don’t use it for live projects.
Also, in general it’s important to differentiate between backup and synchronization services. Google Drive, Dropbox, One Drive, and similar services are designed to facilitate working across multiple devices. Unfortunately, this means that an error on one device will propagate to all your other devices at internet speeds. They’re convenient, but you should also consider an external hard drive backup and/or a true offsite backup service like BackBlaze.
Katherine