While there seems to be an objective universe (external reality), the experiencing of this universe is 100% subjective. So, the "quality" of a life will ultimately be determined by the one doing the living.
Given these premises, wouldn't one "belief system" be as good as the next? We'll make this a hypothetical and remove beliefs that result in harm to others.
We each live from the cradle to the grave. My meaning may be found in seeking objective truths through science and logic. Your meaning may be to immerse yourself in sports. Someone else may find meaning in gardening. Someone else in living as a Catholic monk....
We all eventually wind up in the graveyard and probably completely forgotten in a few generations. Who cares what my deceased father believed politically and philosophically? His existence left a small foot print that will erode to obscurity in time. What mattered was the quality of experience he enjoyed (or suffered) during his waking moments.