Is the Holy Quran exclusively concerned with an individual's actions and behaviors? And is everything a human being does mentioned in it? And is there anything that supports this?

The Qur’an is not a journalistic book that speaks about the actions of people. Rather, it is the Book of Allah, which He revealed to guide humanity, to remind them, to warn them, and to give them glad tidings, and to bring them out of the darkness of misguidance into the light of guidance. It contains the divine legislation by which Allah is worshipped by both mankind and jinn, and it encompasses all that humanity needs for their religion and their worldly life, and what achieves their best interests.