I personally think ENT is AU because of all the TCW shenanigans.
Compare episode TNG season 4 x 15 First Contact with ENT 1 x 01 and 02 Broken bow. In the TNG episode Picard says that first contact with the Klingons led to decades of war. Yet if you watch Broken Bow, there is nothing resembling a preamble to war.
That's a very Human-centric point of view, though. Picard talks about "first contact," but he may not be speaking necessarily of
Human first contact. The Federation, even at its founding, was a union of Humans, Vulcans, Andorians, and Tellarites. Maybe the disastrous first contact to which Picard referred was Vulcan/Klingon first contact, and it led to decades of war between Qo'noS and Vulcan.
Or as someone who knows a lot about time travel said, it's [more] like a big ball of wibbly-wobbly... timey-wimey... stuff.
The Doctor Who version of technobabble that doesn't even try to sound "techno," let alone scientific.
Yes, it's true --
Doctor Who is not trying to sound impressive, just
to have fun. To paraphrase Seth MacFarlane, this is a frivolous indulgence that
Star Trek is quite above.