My ISP is a bit crap to be honest, using Talk Talk 2 Mb wireless broadband. I'm used to waiting a couple hours to download most modern games, but 7-9 hours or whatever it was is very excessively slow. Are the download servers in the US? I'm on a fairly up to date skylake PC running Windows 10 (or whatever the latest is) and am not familiar with messing round with DNS since the old days of Win95 or XP.
The client doesn't have a download speed on it, but like I said the file download was a pretty static 220KB/s when I used it. Current download via latest itch client started 1 hour 50m ago and says 1.2 GB has been downloaded, although I have been playing a different (offline) game in the meantime although I doubt that would make any difference. Cheers.