I've happily used Arq (https://www.arqbackup.com/) to get a lot of things into Drive and GCP. You can control your network rate to still get the files uploaded but over a longer time-span below your ISP's throttling.
(Disclosure: I work on GCP but this is a personal, not professional, endorsement)
(Disclosure: I work on GCP but this is a personal, not professional, endorsement)