Sounds like we would have to build satellites with shades that would be selectively turned off and on as needed and only for specific parts of the globe like the overheating cities. Might be able to have some interesting effects forcing weather patterns that way.
However as you say none of that helps the ocean acidification and that is terrifying.
Kinda. The exact quote for it being lowered down without heating up from reentry is "the added ice would cool the water down by only about a millionth of a degree" But yea essentially useless in the big scheme of things.
The ice would be massively better used in space habitats or terraforming other places.
In a strictly technical sense if you source ice in space from something like a comet and bring it down slowly with something like a space elevator it would help a tiny bit. However the amount of effort would be much better spent on either fixing things we are doing or going for one of the crazier but valid options like building satellites that shade something like 1-2% of sunlight etc.
Ok that is one of the most adorable things I have ever seen.