C6300: Devices won't connect. Modem not found by PC despite ethernet. Strange behaviors.

Additional Info:

1. Firmware: V2.01.26
2. OS: Windows 10
3. Fire Stick (brand new), iPhone SE (iOS 14.6), Macbook (Catalina v10.15.7), Android Phone (Samsung), Google Cast

I woke to find devices in the house not connecting to my C6300. WiFi devices see both the standard and 5G networks but fail to join them. Wired computer does not see the modem at all.

Troubleshooting Steps Taken:

• Performed normal power cycles on devices/modem to no avail.
• ISP tried resetting from their end but that did not help.
• Factory reset via the pinhole did not help.
• ISP confirmed fully functional service.
• NETGEAR phone rep confirmed not a hardware problem.

I tried to hardwire the modem into my PC via ethernet cable (had it hardwired in the past) but the PC was showing no signs of the modem even being there. When searching under Devices, I finally found it, but the modem was listed under unconnected.

Abberant Behavior:

Navigating to routerlogin.net did not work on any device initially, as no device was talking to the C6300; however, upon downloading the nighthawk app on my personal phone I saw the WiFi bars appear, and while nighthawk wouldn't work for my device, it had a hotlink to routerlogin.net which actually worked. (I don't understand why or how this happened.)

So by a very round about way I was finally able to get in and look at some stats about the modem:

• Everything is green.
• Status is Good.
• Attached Devices 5 (???)

There was still no connection via any other devices so I decided to set up a Guest network on a whim and THAT works. All devices can connect to the Guest network but none can connect to the basic or 5G network. I also don't understand how or why this is happening.

Restating Issues:

• WiFi enabled devices see standard and 5G networks but fail to join them.
• Ethernet from Modem to PC yeilds nothing.
• Newly set up Guest network is the only thing WiFi enabled devices can join.

Any ideas at all would be greatly appreciated. If any additional info needs to be provided I will do my best.