I haven't read that guide. Speed isn't the issue for literal purposes of my question.
Stability of connection is literally the issue. There's a slow server in every server chain I've tried, and that's 5 separate VPNs, 4 of which are paid-for services.
With a 10-second time-out on their FTP server, if the download stalls for over 10 seconds it restarts. I have yet to see a high-speed, high-bandwidth server in my local country that can provide a 20GB file in less time than I've witnessed resets on this attempt.
Ultimately, it's a fail.