You think it's possible to put any decent percentage of our GLOBAL food production in greenhouses (remember with less light global temperatures go down) within ~6 months?

Billions would perish. If the luckier rich countries did not get nuked or invaded by armies or waves of endless starving refugees then they would be able to save a good amount of their population. At best world development goes back ~50-100 years. At worst, modern civilization basically ends from the combination of conflict and famine.

that doesn’t address the context of the response at all.

is technology helping, or hurting in that situation?

near as i can tell, it is the only thing that could help.

we aso have significant food stores and buffers, and if it was the situation you described it would literally be a ‘drop everything and get working’ emergency. we’d likely do better than you expect.

what else could possibly help besides technology?

But yes, a lot of people would die.