That’s an important question. Let’s cover some important foundations before I answer the question.
The Bible does say every person has ignored God and every person has chosen to put themselves above God. This means, putting their thoughts, their ideas, their values and their systems above God’s. Every person has chosen to create their own god that they wish to follow and serve, whilst denying the true living God. The Bible calls this selfish infatuation with ourselves “sin” and before God we are “unrighteous” - that is our relationship with him has been fractured, we are not “right” with him.
“There is no one righteous, not even one; there is no one who understands, no one who seeks God. All have turned away, they have together become worthless; there is no one who does good, not even one.”
If God were to leave us to ourselves our future would remain helpless and hopeless.
But God, in his mercy sends us Jesus to do what we cannot do. His selfless act of love exchanges his position with ours to rescue us from our own destruction and doom we brought upon ourselves. As you implied, those who hear, and trust and believe in Jesus will be saved.
Unfortunately many times Jesus followers fail to honour and obey Jesus to tell other people from other cultures the liberating power and freedom Jesus Christ gives men and women, boys and girls. As you know, this means many people may never hear about Jesus. However, despite Christian frailty God does offer us a merciful solution. We read in the Apostle Paul’s letter to the Christians in Rome
“For it is not those who hear the law who are righteous in God’s sight, but it is those who obey the law who will be declared righteous. (Indeed, when Gentiles, who do not have the law, do by nature things required by the law, they are a law for themselves, even though they do not have the law, since they show that the requirements of the law are written on their hearts, their consciences also bearing witness, and their thoughts now accusing, now even defending them.) This will take place on the day when God will judge men’s secrets through Jesus Christ, as my gospel declares.”
Thankfully, this means, God in his mercy will judge these people through the law that they lived by- according to the standard they know to be true. We need to remember God is just in his judgement, he will not hold people to account for something they could not possibly know. So those who have never heard about Jesus will not be judged by their failure to follow him.
However if the numbers could be counted I would hazard to suggest that by and far more people know about Jesus than those who have not. And it is what we do with that knowledge that will determine how God views us.
I hope this helps.