Watch The Original Series, Animated Series and old movies where they visit the rim of the galaxy twice, the centre of the galaxy twice and cover 1000 light years in 12 hours at warp 8.4. Now watch Star Trek: Voyager, where their fastest ship would take 75 years to cross 70,000 light years if they could maintain their maximum speed of warp 9.975. Nothing in nuTrek is as big a fudamental change as that is. Much of TOS is impossible Voyager's framework. And yet they directly cross Voyager over with STVI in "Flashback". IMO if you can do that, then nuTrek most definitely can split off from the PrimeTrek universe in 2233.