Unlike tests in other countries like the UK and US, the Gaokao is not designed to promote useful skills in students like creativity, critical thinking, or problem solving.
I think anyone who's ever taken the SAT and (I presume) the A-levels went "wait, what the fuck?" When they heard the above. No standardized test is capable of increasing your creativity or critical thinking, and the only problem you solve is how to get good marks on the test. The video author clearly has an unjustifiably rosy view of the West which borders on standard lib shit.
The rest of the video raises some okay points like the uneven distribution of education resources, long hours, and social pressure. The first two are things that the government is taking steps to combat by providing better access to schools to rural populations, and China recently cracked down on the after school tutoring industry, practically gutting it, to make it more fair for all students and to ensure that they get time off.
Unfortunately, most of the problems arise out of a limited number of spots at desirable universities and intense competition between millions of students. Even if you create a completely fair and equitable system based on merit, the people who get in are still going to be the smartest people who work the hardest.