The incorporation doctrine is centered around the Bill of Rights and criminal law. There is plenty to the constitution that bound the states from the onset, such as the guarantee of a Republican form of government. Almost all of Article 4 for example does little else than apply to the states, save for a few sentences detailing federal obligations to the states.
For what it’s worth, I have no problem with the incorporation doctrine. Any state that would abrogate the principles of the Bill of Rights, has ceased to be American.
I have no problem with a state implementing an official religion. Am I wrong that at the founding of the US Maryland was officially Catholic and Massachusetts was officially protestant? If I am wrong about those two specifics, I am fairly certain that many states had official religions. Was America not America until the 14th amendment passed?
I wouldn’t mind living in an officially Catholic state in the USA. At least that is what I think - since this is hypothetical I might be way off about it being better.