These coal plants are meant as backups. They specifically invented peakable coal plants so that they can fulfill that role. They even optimized the hell out of these coal plants: new Chinese coal plants are the most efficient in the world. These new coal plants also replace a bunch of older, more polluting plants.

A couple of years ago in China it was cloudy, non-windy, and dry at the same time for an extended period of time.

The energy transition isn't as simple as "build more solar, shut down coal".