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…
Also the Spiegel list removes books it doesn't like. https://www.welt.de/kultur/article167043384/Spiegel-verteidi...
But great to include the source.