I have just made a post about this, seems to be happening as soon as I log in to Steam, it's as though it's shutting down my network adaptor at irregular intervals, it doesn't happen when I'm browsing the net or watching an online video.

https://psteamcommunity.yuanyoumao.com/discussions/forum/0/597413835511742344/?ctp=10#c597414091753211437

Resetting your network adaptor resolves it for a while, unfortunately, not long-term.