> would be the worst geopolitical move of the century

From a political perspective, perhaps.

> doing it forcefully just isn't something China would realistically do

From a military perspective, taking Taiwan by force would allow China to, "threaten the sea lines of communication and to strengthen its sea-based nuclear deterrent in ways that it is unlikely to otherwise be able to do." Taiwan would give China access to the Philippine Sea. https://gwern.net/doc/technology/2022-green.pdf