China needs a few years to demonstrate that the Hong Kong option is a lot better than the Ukraine option. That should increase probability to surrender or accept that independence is impossible
It's also necessary to demonstrate that life in China is good. Overtaking the US in nominal GDP is one aspect of that. People on Kinmen can see that directly, on Taiwan they can't. So Chinese successes in space exploration can help get it into the newspapers that China is a more advanced country now and that betting on the US to win is not smart. Producing better semiconductors than TSMC, a company everyone on the island should know about, will demonstrate that as well
But for anyone unwilling to peacefully accept the situation after a reunification war, reeducation is the only option. Send them to the mainland and give them some education for a year. It has worked quite well in Xinjiang. Combined with migration from the mainland to Taiwan there should be no long term issues
The only question is how to restore central government control
Everything depends on who controls the media in Taiwan. China could grow 3-4 more times, but if the people in Taiwan don't get the message, or get the skewed message thanks to US CIA propaganda, it wouldn't matter at all, and the current mindset would continue. Also, you forgot that it's not only about the money but about ideology as well. People in Taiwan are already very deep under the Western "freedom" democracy cool-aid propaganda train. They will say: "Yes, mainland China got richer, but at what cost?", or some similar bullshit, like the other people in the West basically think in the big picture. Anyways, if the US were to be "praised" for something, it is their media and propaganda dominance, also intelligence soft operations. I feel like the only way for China to change the status quo in Taiwan now, would be with practical action (like it did in Hong Kong at the end of the day, but more extreme), otherwise, there is no hope. Btw, If someone can post some kind of study regarding the state of the media in Taiwan (ownership, overall bias, rhetoric, etc...), I would appreciate it, I haven't managed to find anything like this online yet.