Does 2 Samuel 12:23 imply that infants who die go to heaven?

In 2 Samuel 12:23, David says about his deceased infant son: >*"But now that he is dead, why should I fast? Can I bring him back again? I shall go to him, but he will not return to me." (ESV)* Many Christians interpret this as David expressing confidence that he would see his child again in the afterlife. This is often cited as evidence that infants who die are in God’s care and go to heaven. - Does it imply that children who die before reaching an age of moral accountability are saved? - Is David speaking about the afterlife or merely about joining his son in the grave? I'd appreciate perspectives from different theological traditions, especially Protestant, Catholic, and Orthodox interpretations.