How are you "supposed" to download your treasures? Download managers? Or just let the 100GB file sit in firefox download list and potentially get cut off mid-download?

Firefox should have a .part file with the downloaded content written to it. So even if it was cutoff, if you attempt to download the thing again, it should continue where it was at last time.

torrents

Downlaod managers can work with most downloads. If a site is really badly coded it still wont work. Bittorrent is good for this. I recomend qbittorrent on linux/windows, or flud on android.

With bittorrent you want to configure your settings. Set you max upload to half of what your connections upload speed is, or lower, you might have to experiment with this to see what your router and connection can handle. Activate "exit on finish" limit your max connections to 50-100 if you dont have a router with a strong CPU. Enable "require encryption" or use encryption and dont allow non encrypted connections. (Keeps your isp from throttling and helps keep you safer) Disable automatic start when you device boots up (very important)

Then you are all set. Just remember to make sure you dont run it all the time, bittorrent is hard on your router, not that it will mess it up but it will load up the CPU, honestly not much worse then windows built in spyware these days, and try to place the files where you actually want them when creating a download, so that you can reupload to the world. If you move the files after downloading them, then the client cant reupload to other users. You could even consider setting your max upload slots to something reasonable like 24 with a max upload rate of 200 KB/s, and let it run all the time. Be careful when hosting copyrighted content unless you have a VPN always active. You really should these days, they are cheap. I think i payed $80 for a year of proton VPN, a swiss company that isnt as beholden to the giant global intelligence network. You should also support artists so dont pirate unless you dont have a good option for getting your content. Pirated content also has a risk of containing malware and getting you sued.

As someone who lives in the U.S and is always on the road for work, i constantly have to deal with terrible and 3rd world internet infastructure. I am very familiar. Half of my state has about a 40% packet loss rate or something. Idk. Its bad. It drops out completly multiple times per day, cell towers, ISPs, credit card machines, etc. Sometimes you might just need to download from a better connection in another part of your state or something.

I dont have any recomendations for a download manager for PC, but for android ADM, advanced download manager seems to work well. On PC i usually just use torrents. Using a VPN in exclusivly TCP mode can also help, UDP is a lower latency lossy connection, TCP will resend packets until all of them get through. Using a vpn with TCP can help if you have a crappy connection. It wont help much if you are getting multi second drop outs. For that you really need bittorrent, or a download manager. If the zite doesnt work with download managers, and you cant get a torrent, you can try to find a mirror of the download somewhere else. Tey searching for the file name in quotes, like "filename.zip" and then use -website name to remove results from spammy sites. A search might be like, ( "filename.zip" -website1.com -website2.com )