If there is one God and one religion, what happens to the rest of the people who do not belong to that religion? Do they go to hell? [Spirituality & Religion]

Whwt if they are raised in an area which did not expose them to the “one true religion”? For example, there are 1.2 billion Catholics. What happens to the 5.6 billion (give and take on numbers) people who are not Catholic? What happened to the people who died prior to the organized religion or the concept of God Default to eternal damnation?