As a lifelong science fiction reader, I think there are a lot of interesting possibilities. However, I don’t think panicky end-of-us-all speculation is necessary or helpful. We survived the Black Death. We’re a tough species.
I remember when the oceans were going to be the next great frontier for centuries to come. Well, they’re still there.
Another thing is that, if we did colonize space, we would probably split into another species before long. It is also possible that every planet we colonize would have a different variant of the human specifies. You would definitely see humans evolve for space travel.
And that is from the biological perspective. We could also self-evolve by fusing with machines. Arthur C. Clarke (who was a tremendous visionary) also thought that eventually we would become the equivalent of cyborg spaceships.