Try using a good vpn like Express VPN and also try using a different browser. Some browsers are better than others at downloading.
For my phone, I am using Stargon browser along with express vpn. It's really fast at downloading from this site. But I switch browsers very often so that could change. Stargon, Dolphin, CM, Kiwi, UC are fast downloaders on the phone.
I don't use Mac or windows right now, so I don't know much about desktop browser apps.
But I think a change in browser apps and/or the addition of a fast vpn like express vpn or nord vpn will probably fix the problem (especially if you are downloading straight from the app).