I like Enterprise a lot, but it's amazing to me that it's now considered "Classic Trek canon", considering the reactions when it was coming out. When I hear Classic Trek, I think of TOS (and maybe TAS and TMP as well). Here's a fairly *light* example of fan concern over Enterprise canon:
""Regeneration" is the strongest evidence I've seen yet that
Enterprise must become a reset-button series, in which all the events of the show's run are wiped out in the final episodes. There are just too many inconsistencies with original Trek and TNG canon, otherwise....On the one hand, it's good that the producers can say, "Well, the timeline has been changed so we can do whatever we want." But on the other hand, what's supposed to keep us old-time Trekkies grounded, to make it familiar and logical? I'm a lot more impressed when they manage to get seeming inconsistencies to reconcile -- something Pocket Books' authors have done admirably in the Trek series, especially
The Eugenics Wars -- than when timeline disruptions are used as an excuse for rewriting canon. This show's viewership has declined significantly enough that I'd think winning onetime Trek fans back would be a huge priority."
https://www.trektoday.com/reviews/enterprise/regeneration.shtml
There were many more, shall we say, strongly worded reactions regarding whether the series should count as canon.