[Networking] Alternative to Bouncing Router?

For the last several months I have bounced (unplug for 20 seconds & plug back in) the Verizon router (UltraLine Series 3 Model 9100EM) daily to maintain connectivity. Lately I seem to be bouncing it multiple times a day. It’s the same issue I’ve dealt with for some time – DNS errors and socket time-out messages in the router. My wireless devices and my desktop are connected to a high speed Asus router; the only things connected to the Verizon router are the set top boxes and the Asus router. The forums are full of this issue and the “fixes” seldom last for very long. I’m wondering if there is a limit to the number of devices the Verizon router can handle, and whether 15-20 devices is too many. And if I’m expecting too much of the Verizon router, what is a technique I might use to off load it? Since it is connected to the ONT device, it’s still going to be the knothole. My problem isn’t a wireless problem, so I don’t believe Verizon’s new router has anything to offer. Thanks.