Du Xiao Mi's feed

I understand that the MC can't always be super smart etc and I've seen a couple of airheads MCs that are well written so I know this could have been promising...why is the MC so much of an idiot and what's wrong with all those princes? What about world building (I really can't understand this world)? The plot often makes no sense and the characters are flat and inconsistent...where has the quality gone?