I recently had a similar issue. It was the USB to Serial chip driver for windows 10. It would install a basically dead version of the driver that wouldn't let it get a com port.
Put an unmanaged switch between the modem and router. The first time it happens unplug the cable going into the modem and see if it still resets. Next time do the same thing with the cable going into the router.
This should let you isolate which port is being reset by unplugging the connection.
I had a couple switches that would overheat and do something similar. I removed the top of the case and installed a fan and never had another problem.
I have also had switches that if i had to guess were trying to route to the wrong ports. As soon as i restart the switch the problem went away.
My Asus Strix speeds hold very well and the cooling is exceptional. My Asus dual is pretty crap. It's very hard to buy based on branding alone. When i buy a card i usually fit the largest cooler i can from a good brand.
Almost every one of them would need to be reset multiple times per week. We would stop getting calls and customers would call my cell to tell me that our lines were dead.
We tired a bunch of firmware revisions to see if any worked and they all had the same problems.