Chinese domestic flights: Carry-on liquids, gels, etc do parallel US restrictions. You will not be permitted to take water, sodas, or other cans of liquid through the security checkpoint. Note that there are a few airports in China that tend to be even more restrictive but unless you are going to airports in Xinjiang or some in Gansu, you probably won't encounter this.

Checked bags do not have the same restriction, and you may pack your large shampoo bottle and diet Cokes in said baggage....but seriously, you shouldn't need to. You should be able to find diet Coke ("Coke Light") in just about any supermarket or convenience store in Zhuhai. And rather than take a large shampoo bottle, decant what you need in multiple small disposable bottles, which you can ditch as you empty them.