What about native people in the deepest part of the Amazon jungle, who have never seen a Western civilized person. Who have lived their entire lives hunting and fishing and living in grass huts?
Romans 1:19-20 Explains it this way - " For what can be known about God is plain to them because God has shown it to them. For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things hat have been made. So they are without excuse."
Psalm 19 says "The heavens declare the glory of God, the skies proclaim the works of his hands. Day after day they pour forth speech, night after night they give knowledge. They have no speech, they use no words; no sound is heard from them. Yet their voice goes out into all the earth, their words to the ends of the world.
In Acts 8: 26-40 We read about Phillip who was told by an angel to go on a journey, and as he went on the journey he met an Ethiopian who had never heard the word of God, but was struggling to understand it. So Phillip helped him understand it. He shared the good news of the gospel, baptized him and then was taken away by the spirit of the Lord.
That Ethiopian is just like everyone else on earth who seeks to know the Lord. It isn't so much that people who have never heard about God or Jesus will be in Hell, it's people who refuse to know the truth. People who don't seek after the truth. People who reject it when it is revealed. Because these scriptures make it clear that God has revealed himself and will make himself known to anyone who truly seeks him.
God is not surprised by an unknown people group in the Amazon. He made them after all.
Berean Real - Getting the Gospel Right