Internet keeps disconnecting on large file download

For the past few days I've been trying to download a large package of files -- a game -- Call of duty modern warfare warzone in particular -- which is around 100 GB. It works fine for a little bit as I let it run, (for a couple minutes), then the speed of the download gradually gets slower until it hits like 100 kbps which at that point I lose connection to the internet, not only on my PC but any device wired or via wifi has lost connection and I have to restart my modem / router to reestablish connection. I have 200 Mbps and on google speedtest it shows around 90 Mbps download speed. The game, when I first start the download, shows around 5-8 Mbps download speed and as I said slows down until the internet crashes. Is this happening to anyone else recently?