So extend the school day then?

A kid should be able to get taught everything they need in the confines of the school day, outside of that time they shouldn't be given any more work, it's ridiculous. No one would put up with being expected to work for free outside of office hours, so why is it acceptable for children?

You can't 'learn concepts by repetition', that is not how learning works. You can learn a concept & repeat its application to be faster at it.

And that's the problem. What if the student didn't catch the concept during the lesson? He or She needs help by a guardian or be punished for not completing the task.

Same thing with the supposed self management skills. What if the student fails at it? He or she needs help by a guardian or will be punished.

At the end of the day homework is a tool to offload tasks of the school to the guardians of the student. A schools system, that relies on homework, is a system that fails in its task of creating a level playing regardless of socioeconomic background of the student.