You have a lot of catching up to do in school. The declaration and constitution heavily pull for Locke’s Treatises of Government and even older texts. It is not necessarily speaking to a god. In fact Locke brings up Spinoza in making this point. It is moreso that we exist in a universe that functions with certain parameters that are the baseline for our current situation. It’s very generalized. Basically, Locke’s philosophy, which was inherited by the framers of the declaration/ constitution/BoR was that civil society only exists as an agreement among people in order to better their quality of life. If it does not live up to these expectations, people can abandon government and go back to less civil times. Government helps prevent the breakdown of discourse with war being the ultimate opposite of civil society. Basically, the government exists by the people and for the people. The Declaration of Independence is an important founding document in US history for many different reasons, but one of them that is of importance is that is marks the foundation for a unified set of values that would be further codified in the follow-up documents. It was made very clear to all present that when the Constitution was drafted, it would have fast-follow amendments and then continue to in order to reflect the basic foundational values as society and technology progressed over time. This flexibility was intentionally added. The founding documents don’t speak much about the financial system. That came later.

Jefferson was an athiest too, and he wrote that text.

The Declaration of Independence is a statement of values, a list of the ways the Crown had violated those values, and a list of the ways they felt were proper to address those violations, up to and including armed revolt.

The Constitution was an attempt to make a goverment based on those values. It was and is flawed, and should be changed to better reflect those values. That's why "What about the 3/5 Compromise?" isn't a gotcha. It's wrong, everyone knows it's wrong, schoolchildren are taught it's wrong by the government itself.