If you think outside the box, interstellar distances become manageable.

For example, if your spaceship is just a super computer containing human brain uploads instead of biological passengers, you can halt the processor at the point of departure, then resume at the destination. From the perspective of the "passengers", the trip was instantaneous.

Then you can manufacture whatever sort of bodes are suited to the destination planet to put the uploads into and send 'em down. Or make biological human colonists using artificial wombs and frozen stores of sperm & eggs.

It's only interstellar flight as old scifi depicted it that's out of the question. It's a problem of naievete, not physics.