I am really glad you see the danger of geoengineering, and are warning about it. But your story could be so much simplier and more powerful, imho, by relating Landauer's principle systemically to the relevant dependencies, and tracing it through.
Getting the temperature back down on the planet has to involve use of the energy of the sun. It can't be done in any other way, given we know the energy load of humanity, the challenge is to supply that energy in a way that, rather than heating the planet, we cool it instead.
There is only one answer, given there is a need also to provide fuel for all aerospace, which will never really fly on batteries on platforms much bigger than UAVs.
https://eric-bott.medium.com/yes-we-will-be-flying-in-hydrogen-powered-passenger-planes-93779606fff7
Domestic and Community Based Soar Hydrogen Generation would do it.
It would reduce temperature by taking energy from sunlight, which if not used, becomes heat.
In the case of hydrogen, this means for every kg of hydrogen created, 39kWhrs of heating energy is removed from the sun, encapsulated in the hydrogen.
A small community (1 to 3 houses) can easily produce 1kg per day. Multiply that by a few hundred million people 365 days a year, it becomes a lot.
That energy will not be applied to the planet, at least until the fuel is consumed again, and look, we are terrible hoarders, we would be hoarding the vast majority of the hydrogen we would be creating ("for a rainy day"), until we had more than we know what to do with. Then we'd finally sell a little of it. See how this would quickly replace the fossil fuel stocks previously taken out?
Tracing this further takes us to the realisation that here we have a way of accurately tracking and predicting temperature rise, much more accurately than can be done by greenhouse gas theory and we notice also its related to profit.
The planetary temperature rise has to relate to the energy applied to the thermal mass of the planet. Reduce the applied energy, and there has to occur temperature reduction. If we know the change in applied energy, we know the expected change in temperature.
Stop profit, and we stop the planetary destruction, which is the temperature rise. Notice profit is an energy lie in any case, we won't miss it, when we see the benefits of getting rid of it.
To get rid of profit, we have to start monetising creation, which is the economic product created by solar, the rapidly expanding stocks of hydrogen. This is what needs to be monetised instead of oil.
Solar indexed stimulus is what is needed, I explain why and how it works again in the linked article below.
Doing that reverses the energy flow through humanity, where it was negative, extracted from planet outwards via profit and losses to heat, it becomes positive, put back into the planet as hydrogen, from the sun, via us and the solar Ai.
Looks like again I underestimated how much writing it takes to even get a small part of this concept across, but hopefully you get the picture, I will stop here, and point to a link if you would like to see more, it is a complete, closed solution, unlike anything that could come from greenhouse gases:
https://eric-bott.medium.com/forget-greenhouse-gases-ef857af9b168
