Again, talking about biases in state media is nonsensical when we're discussing state policy based on the statements from people in the government. The biases they express are literally the point. The study is on what has CPC publicly said throughout the years. Meanwhile, what China has done over the years isn't exactly a secret either. They haven't been at war since the 70s, they have managed to establish mutually beneficial relationships with the majority of countries around the world, and they're developing in a peaceful fashion. This matches closely what the stated policy is. If you go back on a time scale of maybe 10 years back, you'll find that China has been fairly transparent regarding what their goals are and their actions match their words.