I have a c6300 WIFI Cable Modem Router and it dropps wifi daily

More on my ongoing saga...

So after paying the $99 fee for 6 months of Gearhead support that I neither wanted nor did I need (I'm an IT professional), I was able to get Netgear to help troubleshoot the issue.  After several different calls over a couple week period, each time the Netgear support person guaranteeing me that they would "solve" my problem, I finally got a support person who immediately offered to RMA my C6300.  I paid the extra $15 for advance ship of my RMA device and installed around 10-20-16.  The new modem has been working wonderfully for the past month or so and now all of the sudden has developed the same "issue" as my original modem!  I'm not trying to decide if I want to go back through the same effort with Netgear support and get yet another replacement modem.  Is there any other recourse available to a consumer if we have a device that does this within the warranty period?  Lemon laws?

Anyway, I've trying additional troubleshooting steps on my side while I wait to decide whether to call Netgear.  At any moment, my family has anywhere from 15-35 devices attached to my network and at least 20 of these is usually wireless.  I'm using both the 2.4ghz and 5ghz wireless networks and the devices are a mixture of IPads, cell phones, laptops, xbox, televisions, etc.  One thing I noticed though is we have a Chinese foreign exchange student living with us.  His devices are connected to the network along with the rest of my family.  The two times that this issue began, was when he had a friend of his (another exchange student) come stay with us for a couple days and bring his devices.

Is it possible that this issue could be related to "foreign" devices such as cell phones not working properly or causing communication issues which locks out the wireless networks?  Probably could call Gearhead support and ask but I have absolutely zero confidence in their technical knowledge.