Is it possible for a stand-alone router to cause a modem to drop its internet connection? I’ve searched Google and see contradictory information about whether this can happen or not. Most sources indicate that a router itself can’t cause your modem to actually lose its connection to the internet.
I'd say it it's somewhere between unlikely and extremely unlikely. And it's simple enough to test: swap out the router or connect a computer directly to the modem's Ethernet port (a modem reboot will be needed).