Internet becomes inaccessible during a browser download

I have built a new PC. I have updated my WiFi adapter drivers, flushed DNS. The internet speed (download speeds tested on the desktop) is very fast, reaching 40-60Mbps. However, Whenever I start a download on ANY browser (Chrome/Firefox/Edge) the internet becomes inaccessible for anything else except the download. The download speeds are great but when the download is in progress, if I try to open/load any page/content on the browser or access internet from any other application, I get the no internet issue. I'm at loss about what to do since I have already tried reinstalling network drivers,

Question by Vivek on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.