are you wanting to use it as a modem only? Or just disable the wifi? 

Either one would work. Still want the modem functionality without the wifi on.

modem only mode: General FAQs: SBG6700-AC (v8.6.x): Bridge Mode Setup (salesforce-sites.com)

and here’s a guide from the forums on turning off the wifi. 

Is there another way to disable WiFi without having to put my cable/mode in bridgmode? | Community (surfboard.com)

Thank you for sending these. I’ve tried typing in 192.168.0.1 into the address bar on both computer and phone and it won’t load anything. I’m not getting a message like the troubleshooting says might happen.

try 192.168.100.1

Still no luck accessing on phone or computer 

I suggest you to login the webpage without co-axial cable.

I have tried logging in across phone and computer devices, browsers, and locations and these 192.168.100.1 and 192.168.0.1 pages never load. Thanks for the help here!

Did you try a factory reset on the device? 

I tried resetting the surfboard but no luck. I have tried both Ethernet and wifi connections on both computer and phones across public and incognito windows across edge, safari and chrome. What am I missing? The webpage has never loaded the arris login for me. 

if you have a windows computer connected to it and open the command prompt, type ipconfig. Whats the default IP address? That address should be the modems address

Thanks again for your help here. The default IP is the 192.168.0.1 . I tried the factory reset and troubleshooting last night super frustrating. I saw a Reddit strand with similar issues and came across this. Would manually setting the IP work? 
 

To access the modem, your PC should be connected directly to it. It's probably not going to do DHCP so you will need to set an IP manually on your PC, then type the modem IP in the browser.

I checked the ipconfig again this morning and the Ethernet connection is showing a different default gateway, IPv4, and IPv6 from 192.168.0.1 . Should I change from automatic to manual on IPv4?

Could you let me know, when you are login to the GUI web portal 192.168.0.1, is it redirecting as unsupported protocol.

http://arris.force.com/consumers/articles/General_FAQs/192-168-0-1-uses-an-unsupported-protocol