Perhaps try enabling HTTPS mode, if you have not already:
Edge is a browser. Microsoft’s only current browser.
Somewhat confusingly, it is based on the open source Chromium browser engine which was originally a Google invention. Google’s Chrome browser is very much the same app as Edge deep under the hood. Which is good news for website compatibility. But each of Edge & Chrome have lots of idiosyncrasies in how they deal with user-level preferences, features, and suchlike stuff versus how they draw a webpage on the screen.
What is the Google Store? On a Windows computer?
Yes, or it was called Google Play? I should have mentioned that part.
Which means you installed the Android version of the Discord app on a smartphone or tablet.
That is different from using a browser on a desktop OS like Windows.
Yeah, I’m a bit confused here. Was the issue on a Windows laptop or an Android phone? Or is there more than one device involved?
No, it’s a PC. Just the one device.
Do you mean you got it from the Windows store that I linked to? The Google Play store shouldn’t be involved at all, unless you somehow managed to install the Android version on your Windows PC (usually not doable without a lot of hoops). Sorry for the confusion here; not sure how we went from a Windows desktop app to the Play store… 
Anyway, but the desktop app is now on your PC, and that works 100% fine… but you can also log back in on a browser now and that mostly works now, except for a few missing icons? Am I understanding that right? Like you went from completely unable to access it through a browser to being able to access most of it?
That is even more bizarre. Does incognito work any differently now?
Are you even on a Windows PC…? Are you maybe using a Chromebook or something similar…?
Yup. I got on through the email verification the app sent. Of course, if I refresh that page, it kicks me out again. And yes, it’s a PC, not a Chromebook. Lemme try incognito again.
EDIT: Nope, incognito is still a no-go. 
An update that I suspect is connected to my other woes: I can’t download any documents from emails to my computer. Very weird.
And yet another update-I believe I figured out the culprit using Agatha Christie logic-what programs did I install around the time the errors started happening? Aha!
So what was it?
Something called TotalAV. It’s a virus-protection program but apparently, it was a little overzealous.
Thanks for the update.
More I wanted to boast about my own success! 
I’m getting a PR_END_OF_FILE_ERROR when trying to access Discord, and it started after I refreshed a slow-loading page. This usually means the browser (like Firefox) couldn’t finish setting up a secure connection. It can happen due to a VPN, antivirus, or network glitch. I tried turning off my VPN and antivirus, then restarting the browser and router. Clearing the Firefox cache or trying another browser (like Chrome) can also help. If nothing works, I’ll try using mobile data or another device to test. It occurs in Firefox when the browser cannot establish a secure connection with a website. This problem occurs on the client side and is associated with cipher suites and instructions for securing and verifying network connections using cryptographic protocols such as SSL and TLS. There are different ways to fix the error, which you need to understand in detail.
I hope it helps!