It is unlikely that we will ever understand it. Everything (the word), is to have a better understanding than what is represented by it, which is impossible. As if we were omnipotent and I want to build a weight that you can not lift. (The exclude each other.)
To understand everything (in the sense of just those things interact most) is also impossible.
For every day we interact with other people, experiencing all sorts of
sensations, we have millions of thoughts and flashes of imagination,
etc.. To understand just a simple day of our lives completely, from all points of view, we need a few millennia.