... but the specific strength does come into play when discussing the costs of hardening and mitigation.
This event is twice as powerful as the previously known largest event.
This should not surprise us, by the way. I'd expect major solar storms to follow a Zipf's law distribution: https://en.wikipedia.org/wiki/Zipf%27s_law
That means that the power is inversely proportional to the frequency. This is common. You see it in word frequency, river length, population sizes of cities, etc.
So over a 15,000 year period, the biggest solar flare should be about 2x as big as the next biggest. And random Miyake events, which we've had 9 of over roughly 50,000 years, should be about 10x as big as a once every 160 year event like the Carrington event probably was.
All very rough, of course. But it may help give some intuition.
Forget about civil unrest. Chain of command in the military goes down and every unit is on it for themselves. Imagine generals not knowing if the President is still alive.
The Carrington event in 1859 caused serious damage to telegraphs, for instance.
It's a risk that is more once a century than once a millenium... so we may very possibly see one this century.
Considering how reliant we are on electricity, if everything goes down for more than a couple of days at most there is bound to be extremely serious civil unrest on a global scale: just imagine no access to money and thus not being able to buy food, fuel, etc. and then supply chains shutting down anyway.