This was asked before in 2020 and I'm now having the same issue.
"I just received my EX7700 device.
After having powered it (green led) there is no NETGEAR_EXT wifi visible to continue the configuration.
Any help?"
This is a new Nighthawk X6 Mesh Extender purchased.
I did set it up using wps. NETGEAR _EXT did not appear. Frustrated, I turned off EVERYTHING connected to my Wifi and my Modem. Set everything to Factory Reset and reinstalled everything. This time, I used the Nighthawk app to install the extender and got the same results... no NETGEAR_EXT visible.
Re: EX7700 - first launch no visible NETGEAR_EXT wifi
If you're hitting the wps button it sets it up in mesh mode which has the exact same ssid as the router. So it doesn't show up as separate. You could look in your attached devices list of your router and see what ip address it is.
Or when you factory reset, make sure not to hit the wps button
