The community has characterized spaceweather and the solar events that produce it pretty thoroughly, at this point. Like you say, we can't do anything, defensively, the only thing we could do would be to warn the world what was about to happen. I dunno if it would be the complete undoing of civilization, especially if we got our messaging right (uh oh, we're notoriously bad here), but it'd certainly be a setback to lose a bunch of satellites in low earth orbit. It's probably mostly military satellites in LEO. Almost all of the commercial comms satellites are up much further in geostationary orbit, but they could still see some impacts. Not enough folks with the knowhow out there to perform the volume of emergency station-keeping ops needed to prevent at least a few collisions. GPS satellites are in a much less crowded orbit, they might be OK.

Whether or not we've sufficiently fortified the power grids for a Carrington-level event is the real question. Luckily, I can't recall any recent issues with power grids, especially not in my neck of the woods.