I don't think it's possible to have genuine separation of church and state without state atheism, not just "secularism." The problem is that if religious people can run for office they will just make up "secular" reasons for their legislation. It tends to be so silly that most of the time they don't even hide it: they will outright argue to the public that they're implementing the law for religious reasons, but will just write down a non-religious one for the record.

Take same-sex marriage in the US for example, where US politicians started to float some argument that the definition of marriage is between a man and a woman therefore if you allow it you're abusing the definition of words. Like... c'mon, not a single soul on earth finds that argument actually convincing. It's just a silly argument made up to justify a religious-motivated law.

You cannot have scientific management of the economy ran by people who believe in magic. Sorry.