SMRs make me so goddamn miserable. We already know how to build nuclear plants. Build those! We're kind of on a tight deadline here, maybe don't waste time trying to invent a less efficient reactor that's supposed to solve a problem we don't have.
We already have working carbon capture technology, too. It's called plants. Thanks to deforestation and ocean pollution we're making negative progress creating CC machines, nice job.
The thing that really grinds my gears about the escape to Mars plan is that Earth is already habitable (for now) and Mars is not. If we can make an uninhabitable planet habitable, we could just make the already habitable planet stay habitable. There is no scenario where terraforming Mars is easier than, uh, "terraforming" the Earth.