Where does it say that 600km/hr is gonna be the operational speed for China? If it's the operational speed, it means that the top test speed should
already be somewhat comfortably above 600km/hr, like 650km/hr.
Like Japan running 500km/hr operating speed while capable of running 603km/hr. Top operation speed is not gonna be the same as top testing speed due to cost efficiency and safety concerns. There has to be a margin of safety. The top testing speed is currently still held by Japan, and there are already videos of the train running at that speed.
And isn't it too early to talk about top operational speed when the track still hasn't been build for testing?
So it's likely not talking about operational speed.