I needed to send a copy of my website to someone recently for some complex recoding. The total size is around 15gb and the total number of files over 250,000 (I host a lot of photo galleries).
Tried regular Google Drive, Dropbox, OneDrive etc but all ran into problems for one reason or another.
The solution in the end was to Zip the entire site and upload the zipfile to Google Drive. The zipping itself took several hours but the upload to Google Drive was very quick compared to trying to upload the original files.