Is this a one-time transfer or repeated? How automated do you want, as opposed to, say, you using a GUI? Do you want two-way updates (sync) or one-way (copy)? What OS is server (will limit software selection)?
The easiest cross-platform one-time copy is with “Upload folder” in a web browser at a Google Drive folder. Drag-and-drop of the folder might also work, and some file managers (even on Linux) can do Google Drive.
For repetitive or scripted copying or syncing using a cross-platform software install, rclone might be useful.
Cyberduck is also very cross-platform and seems to have mainly a GUI focus, but also has a CLI available.
EDIT: Actually the questions are more complex if this is repetitive. Should deletions be copied (this is what “sync” frequently implies)? Should files that are already there on Google Drive be blindly transferred again, whether or not there are changes? If you need something smarter than a copy, possibly rclone will do best.