Also can't log in via a web browser using the router's IP address

What browser are you using? Happens with MS Edge or Firefox? 

Has a factory reset and setup from scratch been performed since last FW update? Orbi Systems Manual Factory Reset Process | NETGEAR Communities

How do I install my NETGEAR router using the router web interface?

What mobile platform do you have? 

How was the FW updated on the system? Manually or via Auto Update? 

Be sure to disable any MAC Address randomizers on phones and pads while at home:
NETGEAR Mobile Applications and Android/Apple/Windows Devices FAQ | NETGEAR Communities

What is the Mfr and model# of the Internet Service Providers modem/ONT the NG router is connected too? 
Be sure your using a good quality LAN cable between the modem and router. CAT6A STP is recommended.