[Zubersoft]

If you backup to the device itself using the "Local File" option, does it succeed? I just want to verify. You can also try using the "System File Browser" option to select the destination, and use the Google Drive app to select the destination through Google's file picker. I should add that I'm not seeing any issues on my end uploading large backups to Google Drive, so I'm not sure why you are encountering that.

Mike