Putting aside for the moment regarding the ‘precious things’ found and not found; just move to the part about ‘steel’. Steel was not invented until AD1100 or thereabouts. It was called Damascus steel at the time. This is way out of date for Nephi using the term ‘steel’ in the Book of Mormon. But you still have to go back to ‘yes there were precious things’ to ‘they were not found’ regardless of the fact whether or not they were used. There’s a contradiction there that you can’t answer. Nephi is saying the manner of construction was like unto the temple of Solomon and you’re saying that it wasn’t.
NO that is not what I'm saying.
If they worked with Iron could they not have found the secret of steel. I understand you are saying they didn't know how to refine Iron.