I was thinking in terms of quality of life and number of individuals who would be experiencing it, not long-term species survival.
We’d be knocked back to square one. Basically the situation on the ground would be medieval.
Plus there’s the worry that in the chaos following a civilization ending solar flare that the nuclear powers might freak out and launch on each other. So we might off ourselves anyway.
With a big enough EMP all the nukes will be fried.
I can’t remember if it was Von Bruan or Einstien who said it but he predicted that the secret weapon of WW4 would be the stone ax and they were likely right.
It appears that humanity has already had to hit the restart button at least two or 3 times due to major catastrophic impacts and volcanoes., and if enough of us survive the next apocalypse we’ll just do it again.
Unfortunately such an event would probably be the best thing for the species in the long run as it would pretty well wash out the gene pool.
I’m not rooting for an apocalypse but I get your point.
I believe it was Einstein that said ‘I don’t know what weapons will be used to fight WWIII but WWIV would be fought with clubs and axes’.