I think this is the main thing. While the Mongols and the Manchus defeated China militarily, they were assimilated culturally within a few generations. Even before the Manchu invasion began, the Manchu leaders were larping as Chinese rulers. Chinese culture always won.

But in England and the West in general, China found an adversary that could defeat them militarily, and which had no interest in adopting their culture or civilization. Quite the contrary, the new foreign invaders were disrepectful of Chinese culture in a way that was new and shocking.