Best for @jadecricket to test fully.
I index a few Google Drives that I share with my family. Not noticed any issues, but did not dig into looking for problems. Maybe problems lurking. Dunno.
My preference would be to use Dropbox, but my family resists using Dropbox, sadly. Irrational.
To be honest, once the files are put into Google Drive for sharing, there is really no reason to index them into DEVONthink anymore. So I tend not to. So my best advice that unless there is a compelling reason to Index into DEVONthink files on Google/Dropbox/Cloud/etc. then don’t.