As a repeated note I will absolutely need a China strong enough to exert influence. If you rape the shit out of China it invalidates my story-arcs and I'll feel lost and really incapable of going on because I won't have any consistency with anything.

And given the rate of Han-izing China there wouldn't really by any Manchus to support a solely, Manchu nationalist state. So there'd be a good chance it'd just re-annex itself to China proper.