Here I usually track it down on a call to the router all too often. Fixes include firmware updates, settings and swapping in a better router. But here we don't have anything to work with so could be your PC.
Here's a thing. When a client says the problem follows them to their next PC then it's either elsewhere (the router is common here) or they are doing something "just like they did on their last PC". For what the owner is doing we look at what's not stock for say Windows 10. I lost count of Hotspot Shield finds and VPN woes. But again these don't apply. Yet.
Connection drops randomly with the ethernet/pc icon and red x for no reason. Drivers up to date and option to not put the hardware to sleep selected but still happens. This isn't the first pc/laptop I have had this happen to before and it is always after an update sometime down the line. Obviously the troubleshoot function doesn't do anything as usual.