I would think the aerosol or particle based shields would be even easier to remove than something up in orbit. The stuff in orbit will need to be pretty high up if you don’t want it to immediately decay and reenter, so anything in orbit will remain that way for some time. Plus there’s Kessler to worry about. But sulfurs and other aerosols wash out of the atmosphere pretty quickly. That’s the whole reason people talk about termination shocks, and fret that we’ll have to keep the aerosol effort continuously going. To me this seems like a virtue. If at any time we decide we don’t like the effects, we can simply stop. There’s no long term commitment.