The reason for incarnation, the benefit of living with a body instead of as a spirit, is freedom.
As pre-mortal spirits we were immersed-in a general consciousness and could not be autonomous agents. When we were incarnated, we were significantly cut-off-from other consciousnesses; hence enabled to be free.
But as Christians we realise that this body is only our preliminary body, and that our eternal body will come when we are resurrected after death. Which raises the question of why we could not be born directly 'into' a resurrected body - why we had to go-through the 'rigmarole' of first being incarnated and dying.
My assumption is that it has to be done this way, indirectly, because that was the only possible way that God's goals could be achieved. This seems to be confirmed by the fact that Jesus had to undergo the same process as we do - so Jesus needed-to be born and die. It was not possible for Jesus to do what was needed without this.
When we are incarnated into these mortal bodies, we are significantly cut-off from other consciousness. And at death, this being cut-off becomes complete.
What, then, is the situation after death? The body dies, but by incarnation, our body has become part of our-selves - so when the body dies, the soul that remains is incomplete. In a sense it loses its self-determination, its will. The soul after death is helpless - it is in a bad way, but it cannot help itself... of at least it could not help itself until after the work of Jesus Christ.
From the work of Jesus, our soul may be led through death to a resurrection to life eternal - that is to Heaven.
After Jesus, all souls were resurrected; but only some souls are resurrected to life eternal in Heaven; only those who want this and who follow Jesus. This Heavenly life is a 'familial' life of love - love of Jesus and love of other followers of Jesus. Those who do not want this are resurrected to 'damnation' - which is to an existentially solitary state of self-concern.
Thus, Jesus made it possible - through love - to attain to Heaven as eternal resurrected Men. But what of Jesus himself? How was it that he could go through death without a shepherd to guide him?
This is the great 'mystery' at the heart of Christianity - it is the respect in which Jesus was unique. He was sent as our Saviour because he was able to find his own way through the ultimate isolation of death and to life eternal - and from that point he was able to lead all others who had chosen that path of love.
My guess is that it was the perfection of accord between Jesus and his Father - as 'firstborn son of God - that meant Jesus had such love for the Father that he could do what we could not do, what nobody else could do. This says to me that when we die our soul lacks will and agency; but can retain love: love is the only 'thing' that survives death.
So, we die, we become lost, helpless, cut-off - but, if we love Jesus, then that love can lead us to Heaven. And also, it seems, our love for others who love Jesus helps too - perhaps as a kind of synergy. The mutuality of love among Jesus's disciples is further help in our going through death (instead of getting stuck in death).
Incarnation is a cutting-off and disconnection, for the sake of freedom; and love is the restoration of mutual knowing and re-connection.
For this to be viable as a way of salvation, it surely could not depend on the contingencies of human communication. It must be possible for Men to love Jesus when nothing in the mortal world tells them about him, and/ or when the information about Jesus is dishonest or distorted: we must have direct access to knowledge of Jesus if he is to be able to save us.
(Direct meaning without words, or communication media, independent of all persons and circumstances.)
I think this means that when we are dead, and when our souls are in the ultimate passive and helpless state; we must at that point have direct and true knowledge of Jesus, and the possibility of loving him.
Clearly this is not such a favourable situation as already loving Jesus before death, and of being a part of the kind of mutually loving community that was exemplified by the disciples - but I think that something of the sort must be possible (and has been statistically usual) - given the variety of circumstances that Men have lived and died (both before and after Christ) - in line with the Biblical passages that refer to Jesus coming into contact with dead souls.
So, as a minimum, when we are dead, and mere helpless souls, we are confronted with the reality of Jesus and - if we love what we then know - we may trust and follow him to life eternal. This would be helped if we have loved/ been-loved-by someone who loves Jesus; and by the experience of love (obviously, I mean 'love' in the sense of disinterested, self-sacrificing, soul-valuing love).
If we are incapable of love, if we dislike Jesus, if we don't want to live in a world of love etc - if e want a world orientated around our-selves, a world of exploitation rather than love, or if we want our-selves to be annihilated... then we refuse the gift of Christ and choose the state called damnation which is Hell; but which some prefer and choose.