There is a dearth of simpe workable solutions of late since the deprecation of some from the past but an alternative does exist in the form of ExpanDrive for Linux
As in the case of insync it is a paid solution (similar cost) with 1 week free trial but the cost after that is not onerous and indeed, if you decide not to elect to have upgrades then the application remains free with a limit of 20 minutes per session in use. Access to your data always remains whether you pay for the licence and or support/updates or not.
The app loads an icon into the system tray and will handle multiple online accounts such as Box, Google Drive, One Drive, Amazon S3, Dropbox &etc. This is superior to other solutions which require navigation to Other Locations
in Nautilus and is very similar to the way the Dropbox
desktop app performs (although you can still navigate to Other Locations
if required to access your files).
Basically, I would like to create a /home/user/Google-Drive where to
sync my existing Google Drive.
As indicated, ExpanDrive
creates a folder in your /Home
folder: /Home/ExpanDrive
and a separate folder in there for each online account. You can simply specify that folder when saving files and they will be synced to your Google Drive automatically (as is the case with other online accounts).
Installing ExpanDrive
on ubuntu is very simple. Download the .deb
file from the link to your local drive, click on it and follow the prompts to install to your system.
The latest version was released on 16 June 2021 so bang up to date.
As this is potentially a paid for solution (if you choose to, as explained) and not FOSS, just to be clear, I have no association with this package or the developers in any form other than as a user.