Thank you @Rico.
To your point, I think having WAN plugged in certainly helps the WebGUI. I tried Chromebook, and the WebGUI does load fine. On my windows 10 devices with Chrome browser (Version 84.0.4147.105 (Official Build) (64-bit)) , it still just shows me "processing request..." forever. I have to reload the page for the dashboard to show up.
Since my LAN is working , I am not too keen to experiment with it too much. Yesterday when I was trying to setup, I got yelled at by my wife and kids for an hour while there was no network inside the house.
Now I am focused on making the OPT interface work. The primary reason why I got a Netgate device was to be able to isolate my security camera system on a separate network than my home network. I'll start a separate thread for that.