I have contacted the development about my banned characters. Not going to post details yet (in case they read this).
But it comes down to the fact that they specifically know about not using their launcher and what trainer was used. So it seems they developed something that can check very very specifically.
Again, will post updates (and the entire conversation with artix) as I know more.
But at this point I'm going to assume it's not safe to even use a third party software to play the game without trainers. At least for the time being.