Ego is the self that drives your animal life. Our anger, our like, hunger, sexual desire, our motive to earn money to reach ultimate comfort, our need to be admired etc is all related to it.
Soul is the divine thing inside us. It comes from God itself. Through soul, we love, we feel the need of beleiving in God.
Ego has always needs, it orders us to get what it needs, without considering moral values. It covers soul so firmly that, we can not communicate with the ultimate love of God. Love of God is not the simple feeling, in encompasses all the knowledge, science and art that created us and the universe.
?n order to reach ultimate love of God, Ego should be weakened or killed at all. It's what sufism does for centuries. Sufis refrain from all the things that their ego wants, while repeating the holy names of God and praising it day and night. After a while, they reach the love of God. Sufis call it "dying before death", "penetrating mountains of 'being'", "drunken by the love of God", "burning in fire of love of God". After then, their souls enjoy the love of God, God becomes their eyes seeing, their ears hearing, their hands doing. But it's a very hard journey that very few could walk.
So, What these DMT and other entheogens are actually do in that picture? God created human beings in the most exculisive way. The key to the other worlds are hidden in our brains that can be brought about by only pure devotion of our soul. I think sufis train their brain to secreate excessive DMT so that they can reach the love of God. They possibly have some degree of mastery in other world, so they don't just trip back and forth as the one who takes exogenous DMT.
So to reach love of God ego should be killed hence let the soul free.