Why does the quran claim this?

Why does the qur'an claim it is a DETAILED explanation of EVERYTHING (Yusuf 12:111)

When it is neither detailed (3:7, also we can get this verdict by inspecting the nature of verses and the qur'an as a whole being concise and not precise. Often requiring clarification from the prophet and requiring tafasir)

Nor is it for EVERYTHING (No source needed, not every piece of knowledge of the universe is in the qur'an, and even if this might mean ruling its still not everything for the reason above)

Do not take this as an attack, I am muslim myself trying to clear a doubt of mine