The Google drive integration is completely different to the connect one.
It’s not automatic, it’s manual.
It works essentially in the same way that the ‘send to email’ feature works. Which means if you make a change to a file, you have to delete the file on gdrive and reupload it.
Of course it's different. reMarkable are trying to leverage their own solution. It pays for them to make the user journey a little more awkward. But 3rd party integrations still exist and they do still work.
Remarkable supports Dropbox, Google Drive and OneDrive integrations.
I use the Google Drive integration regularly.