..and to Cuivienen there is no returning
Nobody knows.
All the stars in the Milky Way Galaxy orbit around the center of mass of the galaxy.
The orbit of the Sun takes about 250 million years. The solar system is believed to be about 4.5 billion years old, and so the Sun has completed about 18 full orbits around the center of the galaxy.
Because no two stars have exactly the same orbits, stars are constantly getting closer to and farther away from their neighboring stars. Over many millions of years, some neighboring stars will pass far ahead of the Sun in their orbits and some will be left far behind in their orbits.
Thus the list of stars which were within ten light years of the Sun a million years ago is somewhat different from the list of stars which are now within ten light years of the Sun, and that list is somewhat different from the list of stars which will be within ten light years of the Sun a million years in the future.
Here is a link to a table of stars which have passed or will pass within 5 light years of the Sun over the past and next few million years according to calculations.
https://en.wikipedia.org/wiki/List_of_nearest_stars_and_brown_dwarfs#Distant_future_and_past_encounters
The closer two stars pass, the stronger their gravitational forces will change both their orbits. The Sun must have had hundreds of close encounters with stars which changed its orbit during its lifetime.
There are an estimated one hunded to four hundred billion stars in our galaxy, and we only have measurements the positons, masses, and motions of about a billion of those stars, about 0.025 to 0.1 of the stars in the galaxy. And many of the measurements of the positions, masses, and motions we have are not very precise.
So at the present time a computer simulation to track the position of the solar system back in time might might have some accuracy for tens of millions of years in the past, but that is a small fraction of the time since since the solar system formed.
2.
A star forming nebula collapses into a cluster of young stars. The new stars include a small fraction of very luminous and short lived stars emitting intense radiation which drives remaining nebular matter outward until it reaches and merges with other nebulae.
So star forming nebulae self destruct. Each leaves behind a void where interstellar interstellar gas and dust have a lower density than average, and a cluster of young stars.
As the open star cluster orbits around the center of the galaxy, it interacts gravitationally with passing stars and the stars in the cluster are gradually pulled out of the cluster and scattered. So open star clusters in the galactic disc last for only hundreds of millions of years before dissipating.
Neither the nebula that formed the solar system nor the open cluster of young stars that formed in that nebula exist any more, having dissipated into the galaxy in general. It is quite possible that some of the stars which formed within ten or twenty light years from the Sun in that nebula are now over fifty thousand light years away from the Sun mixed in with stars which originated in many other now lost nebulae and star clusters.
3.
According to Tolkien's Middle-stories, the first Elves awoke in a place called Cuivienen, the Water of Awakening. And their travels eventually took them far from Cuivienen, to achieve great glory and suffer terrible tragedy. Perhaps some Elves wondered whether it would have been better or worse if they had stayed in Cuivienen.
The narrator of Chapter Three "Of the Coming of the Elves and the Captivity of Melkor" in the Quenta Silmarillion says rather sadly:
In the changes of the world the shapes of lands and of seas have been broken and remade; rivers have not kept their course and neither have mountains remained steadfast; and to Cuivienen there is no returning.
And with the present limits of our knowledge there is no returning, even in calculation, to the birthplace of Earth.
