We are fundamentaly biurnal, you wake up, (in whatever state you prefer), and then do your thing with a limited (daily provided) resources that are awailable to you.
People are biurnal? No, people are diurnal. People who try to be nocturnal or biurnal are fooling themselves and screwing up their lives and probably negatively affecting the lives of those around them.
There's more than a great deal of evidence and different rhythms to the contrary for your blanket statement to be in any way certain. Many people live long, very productive and healthy lives not being diurnal to great effect, even if most are diurnal.
We are fundamentaly biurnal, you wake up, (in whatever state you prefer), and then do your thing with a limited (daily provided) resources that are awailable to you.
Repeat.