Is that a 404 error? 404 means that you reached a web server but it told you it does not have the requested page, which is the expected result when you specify a nonsense page like 1.
Whenever luci doesn't display properly you should clear the browser cache and open a private window and try again.
And just to be clear you are getting the same results on Ethernet or wifi, and when you connect by Ethernet you are disabling wifi on the PC so it is not connected by both methods at once?
@lleachii: 1. On my display anyway, it appeared (as per below), that your suggestion actually was to enter 192.168.1.1/1 If I misunderstood, my apology. 2. Yes, as you showed, it actually was not a 404 error, it was "Not Found", as below. 3. I did end up resetting and/or re-uploading the latest firmware (multiple times and a couple methods), except yours, because I didn't know how...and perhaps if there's ever another time, I can reference that, to enter the "firstboot && reboot" from a secure shell.
@mk24: 1. Indeed, the page error was actually as pictured above, not a 404. 2. Yes, someone else had told me to disable Wi-Fi (when connected by ethernet), so I did at least remember to do that.
I do 'think', as I posted earlier, that hopefully the issue is actually...resolved (somehow.) I really don't know exactly how or why...so I last speculated (hands upthrown in frustrated questioning), that 'perhaps' the encryption method...somehow...influenced things. But even if so, what caused it all to go awry in the first place, some days ago, I'll likely never understand.
I consider the issue to be at least temporarily 'fixed', for now I think? And lastly again, I do so much appreciate how responsive and kind everyone has been! 
The '1' in your screenshot is from the forum software - it indicates how many users clicked the link.
Testing the link unedited as-is should produce the LuCI page. The goal was to not re-type or alter the link.
Then not sure where those non default firewall rules came from.
