How much more detail do we need than the Romulans fukin' around with Earth's history?I'm good with that for now.
However, I think they've left the door open for a future showrunner to potentially explain the timeline divergence in greater detail.
Memory Alpha has updated it with some interesting information on this Ret-Khan.
https://memory-alpha.fandom.com/wiki/Khan_Noonien_Singh
OG Trek Khan was born in 1959.
Nu-Trek Khan was born around the mid 2010s.
That means the Eugenics Wars in the SNW timeline will probably be around the 2040s or 50s, instead of the 1990s.