Both "optimal way to achieve X given Y is Z" and "setting P as your goal leads to Q" are facts. So in fact science also gives you ways to achieve your goals an

Both "optimal way to achieve X given Y is Z" and "setting P as your goal leads to Q" are facts. So in fact science also gives you ways to achieve your goals and even to evaluate and change them to better suit you. You can see this in very simple model that is chess. The only thing chess engines do is estimate how good a position is. But that's plenty enough to win against any human player. As for "meaningful" lives - culture can be a source of meaning, and it can be a cause of lack of meaning (for example if you happen to have a calling to become a pilot but your culture forces you to become a housewife instead).