In the long term, it’s also possible to alter the atmosphere on Venus until it’s approximately the same as Earth. It would be a massive undertaking, but a hell of a lot easier than getting Mars to a comfortably habitable state. And you could potentially get an entire habitable planet out of the deal, which would be nice.
Kurzgesagt had an interesting video on the topic.
Obviously it would take a significant investment of resources that would benefit some future generation, but not our own. So, back to being impossible, at least for now.