Tolkien's Elves and Men can be regarded as differing, most fundamentally, in terms of how each race interacts with the fact of 'entropy' - by which I mean the inevitability of physical (bodily) change, disease, decay, and death in the mortal lands of Middle Earth.
The Elves have many subdivisions following the 'sundering' that occurred on the Great Journey - which was aiming to take the elves to the Undying Lands of Valinor.
At the extremes of Elf types are the Avari and the Vanyar.
The Avari were the 'unwilling' who refused even to embark upon the Great Journey. These Elves seem to have no desire at all to leave Middle Earth, and will therefore inevitably experience the 'fading' which happens to all Elves who choose to remain in the mortal lands.
Fading is described in terms of the progressive disappearance of the Elf's body until all that remains is an unchanging and immortal spirit. Thus the Avari elude entropy by discarding their bodies, including all for which bodies are necessary in mortal lands.
What remains of such Elves is much like we would call a 'ghost' - either invisible for just an illusory image; and without self-awareness or the capacity to learn - but immortal in that state.
The Vanyar are those Elves who unambiguously wanted to live in Valinor, with the Valar, for eternity (or until the end of 'the universe').
Since they inhabit the undying lands, the Vanyar expect not to decay or die - their bodies are not subject to disease or ageing. Indeed, their condition may approximate to changelessness - which includes that they would cease to learn, and would live lives in such complete harmony with the will of the Valar (amounting to passivity and total obedience) that they would only be creative agents in a very limited sense - only 'within' what had already been-created and not beyond it.
(The Vanyar are therefore much like that Catholic conceptualization of the Angels in Heaven; but incarnated in everlasting bodies, and living in the presence of 'the gods', rather than the One and original Creator God.)
We might therefore see the condition of the Vanyar as analogous with the Avari in terms of 'eluding' entropy by becoming changeless.
And this can be seen, therefore, as the 'destiny' of the Elves as a race of humans.
Changelessness is the 'price' that Elves pay for eternal life.
(It may, however, be that the Elves life is not eternal but finite; bounded by the end of the universe as Tolkien often stated. On the other hand; the Second Prophecy of Mandos suggests that Elves, as well as Men, may be eternal.)
The situation for men in Tolkien's world is the same as for Christians in our world. That is; the bodies of mortal Men (living in Middle earth) are subject to entropy and will inevitably experience change, disease and decay - and mortal death of the body.
After mortal death, the spirit separates from the body and leaves 'the universe'; with the possibility of undergoing resurrection (after the time of Jesus Christ, which came later than The Lord of the Rings) - which is an immortal incarnation (embodiment) dwelling in 'Heaven' - where entropy is absent and all that is Good will be eternal.
It is resurrection that overcomes entropy for Men; and the final situation of resurrected Men is one in which they have everlasting bodies and become Sons and Daughters of God.
The situation of resurrected Men is therefore one of much greater agency and creative potential than is possible for Elves.
What is fascinating about Tolkien's contrasting of Elves and Men is that the two races develop in contrary (if not opposite) directions. Elves begin as much less subject to entropy than Men, and therefore more creative and powerful than Men.
But Elves are less free and less creative as they develop, and eventually almost cease to change; ending as essentially passive and contemplative and with little distinction from their environment (whether Middle Earth or Valinor).
Whereas Men are more and more subject to entropy, and with short lives; which - in many ways - tends to thwart their capacity for creativity and power. And then they die: overcome by entropy, as it were.
After which, Men may be resurrected; and attain to an embodied, eternal state of greater agency and creativity than Elves could ever attain.
The different destinies of Elves and Men, and the contrary direction of their developments, means that there was only a limited period when the two races interacted significantly (the First and Second Ages of Middle Earth); and it was mainly with the intermediate - and therefore more Man-like - types of Elf that Men had much to do: principally the Noldor and Sindar.
And while Elves converge upon the Valar (the 'gods' or secondary sub-creators); Men have the higher potential destiny of Converging upon God - (the primary creator).
So death is the 'price' that Men pay for a resurrected life that overcomes entropy; while (unlike the Elves) remaining capable of change, learning, development and creativity.