6300 years?? Humans would have been there and back long before the descendants would arrive. Likely they would be intercepted and offered a choice of destinations.
The speed of light is too slow for interstellar travel, and the amount of energy required is infinite.........
Maybe.
We all like to dream about super-fast interstellar travel, but barring a miracle, the speed they’re talking about is probably not likely to be improved upon very much.
On the other hand, 6,300 years is plenty of time in which civilization on Earth could collapse completely. In which case space exploration will come to a screeching halt while our intrepid colonists (and there descendants) are in transit.
Sounds like the plot of “Icarus at the Edge of Time” short scifi story. Google it.........
Heinlein and others have shown that the poor bastards in a colony ship will arrive to find the planet already inhabited and thriving from the generations of colonists who hopped the FTL ship that left earth after the tech was invented a century later.