EX7000 AC1900 unreliable WIFI issues despite firmware update

Hi NETGEAR Community!

I have the following problem with my NETGEAR EX7000: suddenly without changing any settings on the EX7000, my WIFI connection to the access point on multiple devices (iPhones, Macbooks) has become unstable since running it without problems for almost a year.

While my internet connection using the EX7000 with ethernet remains stable and maxes out my ISP speed constantly, multiple devices connected through WIFI (both 2.4GHz and 5GHz) experience an unreliable connection where the WIFI signal suddenly disappears and reappears at random times and for random durations. Sometimes the WIFI signal appears on my iPhone but it also says “no internet connection” below it. When the WIFI signal is available and working, the internet speed is the same as when using ethernet (maxed out ISP speed). Also, I have the impression that the range of the WIFI signal is not stable either. All of this happened using firmware version 1.0.1.86_1.0.150 over a period of about a week. I then restored the EX7000 to factory settings and updated the firmware to the latest V1.0.1.94_1.0.172. I’ve been running this version for a couple weeks and the same problem persists.

Can you please help me figure out what the problem is?

The EX7000 is connected to a NETGEAR R7000 router by cat6 ethernet. 

EX7000 settings:

• Mode: access point
• Firmware version: V1.0.1.94_1.0.172
• Smart Connect: enabled
• Shared SSID between 2.4GHz (channel: auto) and 5GHz (channel: 36 + 40 + 44(P) + 48) bands
• Security type: WPA2-PSK [AES] 
• Fastlane Technology: not enabled
• Wireless output power: 100%