The universe expands differently depending on where you are …

Go and have a look. This is huge! Maybe even where you are, you who reads this, wherever you are on Earth.


https://www.space.com/universe-expansion-rate-may-vary.html

The HMS Explorer accelerated to one c, his crew sleeping deeply, each in his own cryogenic coffin. They cruised at that speed following the curvature of the universe. The theory was simple. They would return to their point and time of origin. It would take an infinite time and no time at all, relativistic speed helping. But maybe to a better point of origin. Earth was failing so fast now. No humans would survive another century.

They cruised and cruised. A few died when their cryogenic coffins malfunctioned. But all in all, four hundred awoke when the ship braked out of one c. Earth was in front of them, where they had expected it. But no communications came. No radio signal. No electromagnetic wavelength. They took their shuttles and landed, discovering homo neandertalis at the peak of his society.

Universe was not homogenous. Curvature and speed had brought them back. But not to their point of origin. So, well, they settled the land. Again. Hoping for the best.