This thread here, you have found it, just follow the instructions, not hard: https://gbatemp.net/threads/simple-enable-online-functionality-for-ntr-cheats.442996/ You even posted in it and all:/ Otherwise just use Luma cheats instead, just do some research, don't expect it all done for you...
I decided to get into the series couple days back myself. Played original, it was interesting at first but got very "meh" too quickly, moved to second, was "meh" from the start, then third one was pretty good, still got boring about a while, but I did manage to put like 4 hours or so into it before getting bored (I get bored VERY quickly), so if you want to give one a try, go with the third one.
