I use Dropbox, MS OneDrive, and Google Drive for syncing various things.
My favorite is Dropbox. I trust it with my live projects and it has been flawless.
I use OneDrive for my zipped backups and it has likewise been excellent. If I were ever forced to drop Dropbox, I’d keep my live projects on OneDrive.
Google Drive on the other hand is an unreliable, inconsistent mess for syncing. I only use it with apps specifically wired to it for storing their data. (eg. MindMup, Tabs Outliner)
Besides avoiding Google Drive, this is likewise a very important point. For syncing Scrivener project folders, OneDrive’s setting "Save space & download files as you need them must be disabled. The paid plans for DropBox do something similar, but at the folder/file, where you can set them to “online-only”. You should never do this for Scrivener project folders.
On another note–Scrivener’s automatic zipped backups should have been one of the the first things you reached for to resolve your original challenge, so my assumption is that your backup process many need some tweaking. 
Here’s a post I wrote a while ago on syncing and backups. The post was written for v1 so the menu paths have changed, but everything else is still applicable. It would be worth your time to read the backup section.
Best,
Jim
Best,
Jim