ANSWER:
Allah is The Most Just and Fair.
A disbeliever who had heard of Islam and chose to reject it will never enter Paradise.
A disbeliever who had never heard of Islam will be tested on the day of judgment. His fate will be determined according to how he does in the test.
https://islamqa.info/en/answers/1244/the-fate-of-kuffaar-who-did-not-hear-the-message-of-islam