Robert April clashes with Enterprise because Robert April was the first Captain of the Enterprise. Not some twit named Jonathan Archer. If they'd used April and Sarah Poole in the Enterprise series (with or without the dog; I liked Porthos), I wouldn't have complained half as much. I'd still have complained about the stupid stories, but not about who the Captain was.
That makes no sense in the context of the show. Unless the 1701 is 100 years old and April was alive ( and an adult) in the 22nd Century he couldn't command the ship seen in Enterprise.
There have been spaceships called "Enterprise" in Star Trek prior to the 1701. The ringship seen in TMP (and Enterprise
) is one. So the Enterprise doesn't have to be the 1701.