It looks like Google Drive integration only work if the email used in the Google account is same than the one in BoloForms. That means that I can't use the integration as my main email isn't Gmail and that the two accounts are unrelated. Please remove this arbitrary limitation.
Plus, the fact that we can't change email once signed-up (see https://boloforms.canny.io/feature-requests/p/make-it-possible-to-update-the-workspace-email-and-account) that means that there is no work-around possible.