Publishing a book based on long journal article
I am not a lawyer, but John Wiley owns the copyright of your current article, and if you just copy larger parts of it into the book chapter, the german publisher will need to obtain permission from John Wiley (that would already be the case for individual figures) and this can well involve transfer of money. That they allow you to publish a pre-print or put it on your personal website is a concession made to you as a person, but not to other (commercial) publishers.

To avoid any of that you would need to re-write (and ideally expand) the article significantly.