Unfortunately, this is like saying the English are a different nation than the Germans, therefore English royalty has no German blood. In actual fact, of course, they are pretty much of pure German blood, with Di’s kids being the first infusion of actual English blood in several centuries.
The Empresses of the Qing Emperors, the mothers of the next Emperor, were almost all, for political reasons, Mongol princesses. This meant that the second emperor was half Mongol by blood, the third emperor 3/4 Mongol, the fourth one 7/8 Mongol, etc.
So culturally and by legal descent the Qing Emperors were Manchu, but Pu Yi, the Last Emperor, was probably upwards of 90% Mongol by blood. You could go back and look at the whole line of descent and figure out the actual percentage.
Mongolians were absorbed into Han, both population-wise and culturally. Those who stayed in China, that is.
I haven’t studied Qing royal blood lines and not sure of the Mongolian princesses claim.
I am sure I would have been taught at school and remembered it. (I am Chinese.)