When Christianity says that false religions are varieties of Satanism, it is correct. Every question has only one true answer; any religion that contradicts that truth is leading you away from truth, and is thus Satanism. Unfortunately Christianity is false and thus a variety of Satanism. You can't be atheistic either. Atheism is a religion. If the divine and sacred exist, then Atheism is false, which means Atheism is Satanism. You want your country to adhere to the true religion.
Problem: your country is biologically incapable of adhering to the true religion.
Theology is difficult and complicated, like physics. If you're not an Einstein-level intellect you cannot properly grasp it. Indeed theology is almost exactly like physics because the pre-requisite is a profound understanding of physics. To understand metaphysics means to see that which stands under metaphysics. Physics stands under metaphysics, which is why the name stuck.
There is a way out of this problem: the peasantry doesn't need to understand metaphysics. They only need to do what a metaphysicist would tell them to do. Fundamentalism isn't a sin. On the topic of religion, the layman should think what he's told to think, and never attempt to think for himself. The things he's thinking are at best approximations, because the literal truth simply can't fit into his tiny mind. Unless he independently discovers the missing bits, he is guaranteed to think wrong, and that can only happen if the original assumption of being a layman was false.
(Indeed the literal truth can't fit into a huge mind, let alone a small one, but the qualified theologian can grasp what it means for theories to be approximately true.)
In a real country, religion needs to be a strict hierarchy.
At first, everyone would be taught a local approximation of the truth, with almost everything stripped out. It would be just enough to get by in the crudest sense. This looks like worshipping a specific Egyptian god. "The pangolin-headed god of line assembly orders you to go to work on time." They would not be taught it is true, because it isn't. They would be taught it's true enough for their purposes. Basically the same way regular folk are taught about E=mc^2 instead of E^2 = m^2c^4 + p^2c^2, where p is an infinite polynomial, except the part where nobody mentions that emc2 is an approximation. The emc2 equation is only valid if everything is at rest, with no accelerations or gravitational fields.
For many, this would be enough. For many, this would not be enough. They need a less crude approximation.
When the layman outgrows the child version of the religion, they will have questions. To get answers, they need to go up the priest hierarchy and learn higher-ranked answers until they find the ones that are sufficiently satisfying. Usually this would be about simple things, such as having a friend who worships the neighbouring capybara-headed god. All his friends work in a factory except one, who plans golf courses or whatever. This man would be taught how capybaras and pangolins are in fact different emanations of some underlying principle. He would hear at least some sermons from a higher-ranking priest, who has a better grasp of the whole thing, and thus be able to properly understand his slightly foreign friend without having to give up his cherished childhood values.
The thing about a true religion: it doesn't die if you ask it questions. Ultimately the full hierarchy must exist. There must at some point be a Pope who believes in theology that's accurate the way the standard model of quantum chromodynamics is accurate.
If what the layman is taught isn't true enough for their purposes, they can find something which is.
Probably they wouldn't be taught much at all. Have you ever used E=mc^2 to calculate anything? Every moment spent learning about it was a waste of time. If someone is trying to force you to learn something, check your wallet, because that's what they're after.
Of course we can ask questions that QCD can't answer, but anyone who made it all the way up the true temple hierarchy would likewise not need perfectly satisfying answers. They would be able to handle uncertainty and the limits of human cognition.
Fun fact: a correct name for this theology is Alchemy. Alchemy was always supposed to be experimental theology.
Tantalizing occult tidbit: the Christians have it ass-backwards. God does not create the universe.