Yep, an ordinary federal statute would have sufficed. The 18th amendment was not required, but the temperance reformers thought it would be harder to change.
You have been trying to sell that steaming pile for months. It was BS then, it's still BS, and when you tell that fairy tale next week, it will be BS than as well.
You're babbling again. The 18th Amendment could not possibly have any such effect, since it did not affirmatively require prohibition of alcohol. Absent such a requirement, Congress could end the war on alcohol via ordinary statute, just as they could if they had attempted to prohibit alcohol via ordinary statute in the first place.
Once the power was given to Congress via amendment, and it turned out to be a very bad idea, a new amendment was of course required to correct that mistake.