Hi there,
in Appearance > Elements you have a Header Element ( note when viewing a page you can see in the Admin Bar > Elements menu which elements are loaded on the page and it provides shortcuts tom each ). Edit that element and in its Display Rules set Exclude: Product Archive
Now whilst in that Element, on the Site Header tab you can set the navigation colors you want to use for the Merged Site Header.
Now in Customizer > Colors you can set the colors for when it is not merged.