I agree with your perspective on China's leverage over HK vs TWN.
With HK, Xi was pushing the time table forward.
TWN is a bridge too far if US, Asian and EU allies all maintain a coordinated defense against Chinese aggression towards TWN.
Someone earlier made a comparison to Hitler's early military expansion within Germany. I'm not sure I see the comparison. Hitler strategy was to dramatically expand the land mass of Germany. Xi is continuing the CCPs strategy of whipping up PRC national sentiment over a the province that got away..