It's too early to say definitively but it's possible that the atomic bomb dramatically reduced the number of people killed in war by making great power conflicts too damaging to undertake:
I'd actually guess those casualties would be quite less than WW2. As tech advanced, more sophisticated targeting systems also advanced. No need to waste shells and missiles on civilian buildings, plus food and healthcare tech would continue to advance.
Meanwhile, a single nuclear bomb hitting a major city could cause more casualties' than all American deaths in ww2 (400k).
That's really only true for the Americans, the Russians still don't seem to care about limiting collateral damage and undoubtedly the Americans wouldn't either if their cities were getting carpet bombed by soviet aircraft.
https://kagi.com/proxy/battle_deaths_chart.png?c=qmSKsRSwhgA...
The USA and USSR would almost certainly have fought a conventional WWIII without the bomb. Can you imagine the casualty rates for that...