I just found your posts too, thank you for clearing that up! I was searching desperately for exactly what you did. Didn't know your username at the time ofc or it would have been easy.
no worries, there's way too many pages in that thread.
I'm told this thread: https://gbatemp.net/threads/release-miiverse-custom-image-tool.415505/page-69#post-6787736 is a temporary bypass for 022-2812,
but not sure if it allows you to reaccess your NNID.
Haven't been able to test; preloading Legit Pokemon Sun on the banned 3DS right now, lol