I used to think that only by tying Taiwan economic prosperity with China, can we hope for peaceful reunification. I'm not so sure anymore. Learning from HK case, clearly it didn't work. The ugly truth is, Taiwanese just like Hkers, they don't want to live under Chinese political system where single party rule and state control like censorship is tighter than in HK or Taiwan. Taiwanese and Hkers like to do business with China, but they don't want to be controlled by CCP.
Dealing with HK is easier since it is already under China. Just change things gradually both in HK and in mainland China. I do think China need to relax the control someday, back to pre 1989 or even pre Xi Jinping, where things are more relax.
Dealing with Taiwan is much harder. I now don't believe that keeping Taiwan prosper is helping the peaceful reunification. The more taiwan prosper, the more they want to go their own way. Only by making their economy worse off than China, can China have chance to reunify peacefully with taiwan. Only when the taiwanese are poor, and see their chances of better life is in China, can China change their perception. I say China should start containing the taiwan economy development, by making it harder for taiwan to achieve growth. At the same time, gradually open the job markets in mainland China to taiwanese, make it easier for them to work, start businesses and buy property in China.