I don't think it's that simple.
China is a signatory to Kyoto and Paris.
They do care about reducing pollution, and have managed to do so quite significantly in many cities.
China also has quite a bit to lose: many large cities on the coasts, and worsening water shortage problems.
National security probably plays a large role, and I reckon they would prioritize economy over climate, but the evidence implies that they do also care.
You can think about this as if China had access to the same oil reserves or oil markets as the US does, would they behave differently? Absolutely.
Separately I think eliminating pollution is more along the lines of their country just doing good things for their people. Climate change stances and whatnot I don’t think are the same, nor are the intentions.