Nearly everything the tradition credits to the Duke of Zhou was written down long after him, and the atlas has to say so. The Rites of Zhou, which lays out an idealised bureaucracy of six ministries and is presented as his design, is demonstrably a much later compilation, and its influence ran the other way: reformers from Wang Mang onward used it as a blueprint precisely because it carried his name. The line statements of the Book of Changes are assigned to him by a tradition that also gives the trigrams to Fuxi and the hexagram judgements to his father King Wen, an arrangement which is a theory of how the text grew rather than a record of who wrote it.
None of that makes the attribution empty. Confucius took him as the model of a minister who serves rather than seizes, and says in the Analects that he must have grown old, because he no longer dreams of the Duke of Zhou. The remark tells you what the figure meant several centuries after the fact. So what the atlas records is a real regent of the eleventh century BCE and a much larger constructed figure built on top of him, and it was the constructed one that shaped how ritual came to be thought about. Separating the two is ordinary work in early Chinese history and it is not finished.