After reading A City on Mars by Kelly and Zach Weinersmith I think a O'Neill Cylinder spinning spaceship for artificial gravity type is more achievable than planarity colonisation.
But the main point of the book, and I am fairly convinced of the more I think about it, is that it is a lot of effort and risk for not a lot of gain and we are entirely unprepared for space colonisation.
He's really good at drawing rain for sure