Du Fu is a patriotic poet who cares about his country and people. He usually writes about his dissatisfaction with real life and the ruling class. Full of sympathy for the working people!
Su Shi, Li Bai and Bai Juyi are similar in style, and they all belong to those depressed and frustrated people. They are eager to be reused and realize their political ambitions, but they are cynical people who are not in line with real life and are arrogant and conceited. Based on their personality and real life, they can only pin their feelings on poetry.
Secondly, because of their different times, they have different views on many things, which is also reflected in their poems.