Not quite that thread, it was the guide made from the original thread where this all happened.
https://gbatemp.net/threads/creating-a-north-american-non-xl-new-3ds.381775/page-44#post-5476953 is the thread I meant and that is my post collecting and detailing exactly what I did to make everything work properly, now that I re-read my post, I think the key was using updatecdn and the CSV file I linked to in order to get the update CIA files, since my initial update attempt using 3dnus seemed to be much smaller and did not have all the files I mentioned that were not updated in several system updates.
Interesting that other situations allow the keyboard to work though, in my case it was any time the keyboard tried to load, my n3ds would crash. I'd still suggest trying to use updatecdn with that CSV file from my post so that you can be certain to have gotten all of the update files, and not just the most recently changed ones.