To put it simply, if you compare high school with university, high school belongs to management type and university is captive type.
In other words, everyone in high school is supervised by teachers, learning is supervised by teachers, and life is supervised by instructors, so high school does not have more free time than universities.
Universities rely on self-awareness, without the supervision of teachers and instructors in life, as long as they abide by school rules and laws.
Freedom in college, as long as you don't fail the course, your behavior can be within the scope permitted by law. The freedom of college life lies in that you can choose your study time freely. As long as you don't fail this course, it doesn't matter whether you listen or not.
The deadline for teachers to assign homework is one week. Eat whatever you want in life and buy whatever you want. Universities are generally not closed, unless there are special circumstances, you can go wherever you want.
Therefore, compared with high school, universities are still relatively free.