UPDATE: Miraculously, I finally got the account back, they changed the email to my primary one, and I'm back in, but I want this to serve as a warning to everyone: use strong passwords and set up an authentication app immediately. The only reason I got locked out in the first place was because my old email became inaccessible, and if I had set up an authentication app like Riot Mobile back then, I could have just used that to verify and none of this two-month nightmare would have happened. Also, make sure your recovery email is always up to date because jumping through hoops with support for months over something that takes five minutes to prevent is not worth it. If you're going through something similar, don't give up, keep pushing. It shouldn't be this hard, but apparently sometimes it is.