Can not access NETGEAR router login

Hope you can help.

Specs - Modem: Arris DG3450 (also a router) Router: NETGEAR Nighthawk R7000 Firmware: unsure but definitely outdated since 2017 WiFi extender: NETGEAR Nighthawk EX7000 Internet provider: RCN

I am trying to access router login but cannot seem to do so. I just did a factory reset. Before the reset, I was able to log in but couldn’t update the firmware. After the reset, I can’t log in at all.

Here’s what I’ve tried so far:

• Factory reset router

• Cleared internet cache

• Tried on mobile device and desktop computer

• Unplugged wired connection and tried just wireless connection

• Reset modem and router

• Paused pop up blocker

• Tried via routerlogin.com, the IP address, and the Nighthawk app to no avail

When I try to log in via desktop I get an error that my computer is not connected to the router network, even though it is. When I try to log in via Nighthawk app I get a bit further but it stops working once it checks for firmware. When I download the firmware file off the NETGEAR site manually it just downloads text files and nothing I can actually run or install.

Any help is much appreciated. Let me know if you need more info.