At this level it's not that much of a problem. As pointed out it's capacity not production.

China has built huge numbers of HVDC power lines to move electricity around the country. Presumably their hydro is somewhat flexible. All their new coal plants are variable that's somewhat of the reason why they are continuing to build new ones because they need the fast stop start. It's basically what the rest of the world use gas for, but China use dirty coal instead.

People also look at renewables as if it is traditional power. It is absolutely not. Renewable power will be wasted at times and that's okay, it's actually most financially stable way of operating.

First you reduce fossil fuels plants/hydro to absorb the energy. Then you turn off fossil fuel plants for some time. Then you turn off renewables for a while. This is where somewhere like california/UK/Southern Australia is. At this point you still have expensive electricity at parts of the day but also really cheap (sometimes negative) electricity for significant parts of the year. Only then does it make sense to install batteries.

2024 is going to be huge for battery storage. Especially if the sodium ion batteries work as expected which they are expected to. But even with batteries not all energy will be stored.

This is installed capacity, not total production AFAIK.

Solar, for example, can only achieve about a 30% utilization, compared to about 50% for coal plants in China.