Even if we get there, will there be any benefit to civilization, maybe there are no habitable worlds there and it is not possible to profitably extract valuable resources for future travel.
In my opinion, the most realistic thing is to come to an understanding of how our body/brain works. Then learn how to transfer consciousness from a living shell to a machine (with an emulsified environment for nerve endings, and so on).
To learn how to print bodies, even if it takes as many years as it takes to grow in natural conditions.
Between solar systems or even galaxies, our digital consciousnesses will travel, maybe even copies and once in n years, synchronized in some exact or not. That is, to achieve immortality in a “digital” way, then time will not play a role.
Another problem is spacecraft, so that they can travel with sufficient autonomy for hundreds of thousands or even millions of years (this is probably the main problem).