So how did they make it for the upper class?
Making steel is not hard, as a concept. You add carbon in the process, in the right amounts, until you get steel. I’ve seen Youtube videos where they pull the sword out of the forge and rub charcoal all over it before pounding it and they repeat this process until they get the right combination.
It probably took a long time to reheat, rub charcoal, and pound which is why it would have been expensive.