First, we look at the numbers concerning best case scenarios and see that a few degrees of warming is basically inevitable. Then, we ask how likely it is that well make rapid corrections now - personally I see little evidence of that, but I hope I’m wrong.
Next, try to remember that nothing in the world is disconnected. There’s a long scholarship concerning resource conflict and the destabilizing effects of mass migration. We don’t have a good track record of dealing with this, and I see little reason to expect us to become better at it soon.
The geoengineering idea is especially ludicrous to me - what we’re really talking about are emergency uncontrolled experiments to stave off a worse disaster. We’ve organized our entire global economic system around carbon - any geoengineering project has to not only compete with that, but actively remove more carbon from the atmosphere, which is a problem you’re underestimating the difficulty of.
Meanwhile, we need to worry about positive feedback cycles from various sources of methane, and the rest of the related threats to our biosphere (ocean acidification, wildfire, extreme weather).
To close, what has humanity done to convince you that we’ll 100% restructure our society to collaboratively solve this crisis “once it gets bad enough”?