If I am writing two series of books, by the same author (me), should I use similar colour schemes for both serials, assuming the titles are different?

With billions of pictures, its very easy to find a pretty image as your title page, but I believe it is not a smart marketing strategy to use images that have no connection with each other for each book series. I plan on using similar images for serials in-between serial creations of each book series, but my question is, whether I should link both series of books together by generating an identical palette of structural, colour selections or schematic theme choices, so that both series will look like they are written by the same author.

If I am writing two series of books, by the same author (me), should I use similar colour schemes for both serials, assuming the titles are different?
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