Sinophobia in National Socialist Germany should be interpreted as a carryover from the German colonial era, specifically the attitudes of Wilhelm II (whom Hitler hated), an open Turanist:
https://en.wikipedia.org/wiki/Hun_speechThe Hun speech was delivered by German emperor Wilhelm II on 27 July 1900 in Bremerhaven, on the occasion of the farewell of parts of the German East Asian Expeditionary Corps (Ostasiatisches Expeditionskorps). The expeditionary corps were sent to Imperial China to quell the Boxer Rebellion.
...
Just as a thousand years ago the Huns under their king Etzel made a name for themselves, one that even today makes them seem mighty in history and legend, so may the name Germany be affirmed by you in such a way in China that no Chinese will ever again dare to look cross-eyed at a German!
More about Wilhelm II:
https://en.wikipedia.org/wiki/Wilhelm_II,_German_EmperorWilhelm invented and spread fears of a yellow peril trying to interest other European rulers in the perils they faced by invading China; few other leaders paid attention.[40][clarification needed] Wilhelm used the Japanese victory in the Russo-Japanese War to try to incite fear in the west of the yellow peril that they faced by a resurgent Japan, which Wilhelm claimed would ally with China to overrun the west. Under Wilhelm, Germany invested in strengthening its colonies in Africa and the Pacific, but few became profitable and all were lost during the First World War. In South West Africa (now Namibia), a native revolt against German rule led to the Herero and Namaqua genocide
(
https://trueleft.createaforum.com/colonial-era/south-west-africa/msg4983/#msg4983 )
Wilhelm was also appalled at the Kristallnacht of 9–10 November 1938, saying "I have just made my views clear to Auwi [August Wilhelm, Wilhelm's fourth son] in the presence of his brothers. He had the nerve to say that he agreed with the Jewish pogroms and understood why they had come about. When I told him that any decent man would describe these actions as gangsterisms, he appeared totally indifferent. He is completely lost to our family".[93] Wilhelm also stated, "For the first time, I am ashamed to be a German."[94]
(
http://aryanism.net/blog/aryan-sanctuary/kristallnacht-tribute/ )
It makes no sense to attribute Sinophobia in Germany to Hitler, given his views on Chinese not only early on, as you yourself posted:
Adolf Hitler praised Chinese culture and considered Chinese people to be “Honorary Aryans”.[2]
but also re-emphasized at the end of his career:
https://archive.org/stream/PoliticalTestamentOfAdolfHitler/PTAH_djvu.txt I have never regarded the Chinese or the Japanese as being inferior to ourselves. They belong to ancient civilizations, and I admit freely that their past history is superior to our own
...
I am sure that the Japanese, the Chinese and the peoples of Islam will always be closer to us than, for example, France