Mining water in the outer solar system and delivering it to Venus' gravity well until, in a liquid state, it would cover the surface with an average depth of 10 or 20 miles would help cool it down over the next centuries or couple millennia. The larger problem would be to get it rotating prograde at some reasonable pace. Pursuant to this idea, it would be a good idea to build a density map (Earth's is referred to as the Potsdam Gravity Potato) and slam Venus in just the right spot to push the heaviest part into the axial location. Then add the water.
I read that what makes (made?) Venus inhospitable was
the absence/loss of a magnetic field, which resulted in its ‘good’ atmosphere giving way to its current hellsh atmosphere.