It makes no sense to say that the "14th Amendment was not an originalist concept." Originalism does not mean that we interpret the entire constitution through the eyes of the founders, it means that we interpret the document through the eyes of the drafters. So, in the context of the 14th amendment, we would interpret it as it was originally understood when it was adopted. To say that an amendment to the constitution is not "originalist" demonstrates a misunderstanding of the term "originalist."
Regardless of whether or not the 14th amendment is consistent with how the founders envisioned the nation, it is a part of the Constitution. To the extent that state and local governments could favor/disfavor religion prior to the 14th amendment, they cannot do so now.
So the question would then be whether or not the drafters of the 14th Amendment envisioned that this amendment would prevent cities from drafting safety and nuisance regulations that might impact one religion more than another and whether or not the doctrines and mission statements of a religion that were in conflict with the notion of public good might be taken into consideration in determining whether or not to allow a large religious edifice to be erected within a certain historical district within that city?
Do you think that Congress should have allowed Mormons to continue in Polygamy? Should Muslims be allowed to have multiple wives and beat them at their leisure as part of their religious tradition?
What is the first word of the first amendment?