I doubt they care about TSMC.
The CCP understands (or at least was predicting back with Jiang and Hu) that eventually China will democratize. Taiwan is a democracy right now. Democratic countries almost never re-unite into a single country. I can only name one instance of this happening in the last 70 years, and in some ways East Germany wasn't really a democracy yet.
The CCP knows that Taiwanese reunification will never really happen peacefully. Leaders will talk about it, they'll negotiate a bit, but then it won't happen because the status-quo is always more attractive. They know that their only chance at national reunification is now or in the next 10 years or so.
It's now or never. It has to happen by force or it will never happen. If China swallows Taiwan and then democratizes, that can be managed - a restive province can be placated and bought-off. But if China democratizes before reunification, then Taiwan is separate forever.