China has Geopolitical concerns with Taiwan, but there’s no benefit to invading. They’ve got no political base there yet and no benefit to irredentist occupation as long as the status quo is maintained.

I have an alternative take on this. While China's military and economic position vis Taiwan is only ever going to improve over time, waiting also gives the Cai regime time to try to erase existing political, social, and cultural links between Taiwan and China. There's already signs of this happening, a recent example being schools in Taiwan teaching "Taiwanese language" as opposed to "Chinese language". Even yanks only call English "American" as a joke.

There's also an unknown number of KMT loyalists who grew up in China and consider themselves Chinese. Some even say that if Chiang Kai Shek or Sun Zhong Shan were alive today they'd both seek reunification with China. As time wears on, these people die or retire and are replaced with people with no physical or historic links to the mainland.

Also, right now China seems to have penetrated the RoC military to an almost comical extent, so there's a bloc on the inside who would probably consider laying down arms rather than fighting fellow Chinese. Who knows if that'll still hold true in 20 years?