More, but not less
The principle applied here to man's nature seems to apply very widely, including to other questions discussed in this site. (For instance, the life hereafter is an enhanced continuation of the present life, and the one God is like a society known as the "Trinity"). But first things first ....
Man is more than a beast, but not less.
The beasts that most resemble us are apes, and this is where we must mainly look as we try to understand our instincts.
Human behaviour is not determined by irresistible instinct but by choices, but such choices refine, rather than repressing, instinct. Every attempt to repress instinct eventually provokes an overwhelming backlash.
[Such a backlash] is simply the movement after a long tension or standstill, like waters that break loose after long accumulation. This will happen in different periods of history when things have reached a certain one-sidedness. Then suddenly the whole thing will crash down, in a sort of revolutionary outburst of energy that has been too tightened up, put under too much pressure; the steam begins to sizzle out somewhere or the whole boiler explodes.
C. G. Jung, Lecture on Neitzsche's Zarathustra, 26-Feb-1936.
Nature, outraged by one extreme, avenges herself by flying to the other.
C. S. Lewis, Preface to Third Edition of The Pilgrim's Regress, c.1943. I learned the "more but not less" formula from Lewis, and much of what he meant by it is helpful to healthy human development, though I cannot vouch for every use he made of it, and I fear that he may have accepted the Additionalist belief that human nature would have needed grace to be "superadded" (Aquinas' word) even if man had not defected.
We can follow our conscience without denying our animal nature.
(Abstract Humanism or Cultural Marxism, Existentialism) "We should follow our ideals and reject instinct completely. Man has no fixed nature, we can be whatever we choose to be. Humanity is what matters; sex is irrelevant to all the important issues of life."
Whence comes that "should"? It seems to be plucked from the air. I see no basis for it. This approach drops us back into the abyss of moral relativism.
(various forms of Platonism) "We may be trapped in animal bodies, but reason guides us, and often contradicts instinct."
As explained elsewhere in this site, reason needs a starting point. In itself it cannot tell us what is right, it can only help us clarify and develop ideas based on something else.