As far as I know the Spiegel list, which has a lot of media and book shop presence does not count Amazon. The GfK in German has an exklusive deal with Amazon for data, and they do not deliver the Spiegel list data. The Spiegel list also uses an additional voting scheme among their journalists. I have found the Spiegel list a bit weird for years, it contains a lot of highly light reading or polemic stuff like that guy…
I just compared the two lists, and there aren't many differences: only one of Amazon's top 10 didn't make it onto the SPIEGEL list ("Homo Deus"). The lists are at https://www.amazon.de/charts/2019-08-11/mostread/nonfiction?... https://www.spiegel.de/kultur/bestseller-buecher-belletristi... It's all German, obviously. And note that Spiegel has at least two different lists, for hardcover and paperback (plus a few more,…
However if I only look at a single Spiegel list of 20 items, e.g. hardcovers there are only two items left in common.
I think you will agree that a book sales data analysis that has not made a successful effort to include one of the biggest book sellers in Germany for years can still safely be called garbage. It is baffling for me how much reputation the Spiegel lists still have.
Also, the hardcover Spiegel list has entries like the new book by Spiegel journalist Todenhöfer on rank 10 (rank 2129 on Amazon Germany right now).
[1] I ignored the Spiegel audiobooks list because this data is irrelevant without Audible.