All downloads fail regardless of browser!

Ugh, sorry to hear that, but thanks for the quick response! If I have any luck I'll let you know.

Thanks @TairikuOkami
SG TCP Optimiser fixed this problem for me

I was having the same problem as other people in this thread where I found it near damn impossible to download anything on any browser. All my drivers are up to date as well as BIOS but my computer hasn't been able to load videos on certain websites and download files without file managers (torrents/FDM) for months!
Using SG TCP Optimiser worked immediately when I ran it as admin, set it to optimal settings and restarted my computer

Now I can load gfycat.com for the first time, as well as watch lecture videos for university, as well as download large files. :)

Thanks for the TCP Optimizer recommendation, TairikuOkami. I was having constant failures for browser downloads using an Archer TP-Link wi-fi adapter to connect to a Vodafone router, despite the connection being otherwise fine. Started using TCP Optimizer and the issue appears to be gone.