Have you tried alternate download mode on the web download page? There's some info here (page is old, but link still exists) https://itch.io/updates/alternate-download-mode-and-improved-download-text
Turned it on, no difference at all
Those are served from entirely different data-centers, so if the speed is exactly the same then I would think something else is going on. Maybe you can test on a different internet connection?
