Question:
What about those who never had the opportunity to hear about God?

Answer:
Those who have died as children (under the age of accountability) will go to heaven. For the Lord Jesus said: “That in heaven their [spirits] do always behold the face of My Father which is in heaven. For the Son of man is come to save that which was lost” (Matthew 18:10, 11). Contrast Luke 19:10 where we are told regarding adults: “For the Son of man is come to seek and to save that which was lost.”

In Matthew 18:1-5 the Lord tells us that we must come “as” a child simply trusting His Word to enter the kingdom of heaven. So it’s important to teach children the truth. David knew he would be reunited with his child that died: “I shall go to him, but he shall not return to me” (2 Samuel 12:23). Death for the Christian is to “depart, and to be with Christ which is far better” (Philippians 1:23).
All who have not heard about the God of the Bible or Jesus are accountable for the knowledge that they have though it be only the light from creation, which presents God:
“The heavens declare the glory of God; and the firmament shows His handiwork. Day unto day utters speech, and night unto night reveals knowledge. There is no speech nor language where their voice is not heard. Their line has gone out through all the earth, and their words to the end of the world. In them He has set a tabernacle for the sun, which is like a bridegroom coming out of his chamber, and rejoices like a strong man to run its race. Its rising is from one end of heaven, and its circuit to the other end; And there is nothing hidden from its heat” Psalm 19:1-7).
“For the invisible things of Him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse” (Romans 1:17-20).