The Eugenics Wars and World War 3 are the same in TOS.What episode did they move it in?
"Post Atomic Horror" is related to WW3, seperated from the Eugenics War in the 1990's.
If not Gene, who else?
Because Gene held in his TMP novelization that TOS wasn't literal history.Or maybe it might've been in an alternate Timeline all along because TOS has critical events taking place in different time frames compared to SNW.
It doesn't change the enjoyment factor of SNW either.
It can and may you find that way as pleasant.Different Timeline continuities would help answer for any historical mistakes.
I'll continue to enjoy things like MASH despite anachronisms and inaccuracies.