Success Rate 99%
If your Xbox One X fan is not loud, but your Xbox One is still overheating, it can be the fan itself that's has failed and has stopped working. The issue is probably due to the console being unable to cool itself down, or if the fan is working as it should it's probably because it has never had a yearly service. The biggest risk of skipping a yearly service is the main processor overheating to the point of failure, which cannot be repaired or replaced. Eventually, excessive heat can cause other components in the Xbox One to fail as well.