https://fossbytes.com/google-drive-backup-and-sync-app/
I'm a little too paranoid to test this but, because the process will probably require removing file size upload limits, it should be possible to do everything (including portable software) inside a huge Veracrypt (or similar program) volume.
Notably, this is the first time I've found a use case suggesting that "stealth" status should include the temp folder.