Frontier Communications → Re: Disabling NAT on Arris NVG448BQ

You're not able to click the option to turn cascaded router on? The boxes are grayed out if you leave the top box to "Off", or is even the on/off toggle for it grayed out?

Correct. No matter how I change the other settings on the page I'm unable to turn on the cascaded router option.

If I understand your issue, your wanting wireless on the NVG448BQ enabled, which would conflict with the unit being a bridge. Turn off the wireless and add an AP on your firewall/router LAN would be the correct way to do this. This isn't a fault with the router as there is no way to route packets the radio to the LAN of your firewall/router when the NVG448BQ has no IP address ( bridge mode is layer 2 )

All wireless has been disabled on the Arris NVG448BQ and it can't be put in bridging mode as they require 802.1x with DHCP on the ONT WAN interface.

Why would there be DHCP enabled on the WAN?

In bridge mode, the router is just a layer two device ( No IP address ), the DHCP would be from your firewall/router not the Arris NVG448BQ

Sounds like this would be the source of your issues

DHCP, wireless, and the firewall should be disabled on the Arris.

Your main router should do all the work.