Conveniently in such conversations people never bring up where these compounds go when they "fall out". In fact they precipitate or are deposited on surfaces in the form of sulfuric acid. This harms plants and causes all manner of respiratory issues. There's a reason the EPA has fought so hard to reduce SO2 emissions.
I get the impulse for unilateral techno-optimist solutions but continually releasing sulfur dioxide into the air is not a sustainable option in any respect. Sustainability and "more, faster" ideologies are not compatible. You will be imposing health risks on plants and animals that many simply will not be able to mitigate for themselves. It is always apparent very quickly in conversations like this that the people proposing such "solutions" spend most of their time indoors in filtered air.
SO2 is a short-term, fast-acting, and reversible cooling option. That is why we need to massively adopt it ASAP.