These amendments are not legislation, and they are law. The amendments modify the constitution to state what is allowed or not allowed. The clause you site about congress having power to enforce means that congress is enabled to build a legislative structure around the amendment “law” to ensure it is properly enforced.
Consider the first amendment. It starts with “Congress shall make no law”. Using the logic you present, the first wouldn’t be “law”, either. IMHO.
The First Amendment does not contain the clause I referenced and is not relevant.