Large areas of solar panels, engineered to reflect as much as they can't use, would be a good double benefit. Excess electricity could be opportunistically used for GHG capture or the panels could maybe flip over and become mirrors.
An orbital umbrella that we could modulate such that we can deal with unanticipated consequences could also be ok.
I'm sure there are tons of other approaches that give control in both directions on reasonable time scales. Obviously cutting emissions Right Now is super important, and megaprojects shouldn't distract from that.