Years ago, I saw an interview with someone who was or had been in Special Forces in the military. He talked about how hard training was and that he got through training by telling himself he was just going to stay until lunch. After lunch, he would mentally commit to the next hour or two or to making it to dinner. This completely changed my concept of such people and became a cornerstone for getting me through a lot of challenges in the last roughly decade.
People who do hard things aren’t simply awesome at everything or blessed to come from the right family, have the right education etc. Some of them are getting through hard things by managing their emotions and psychology with some of the same tricks used by political prisoners being subjected to torture and trying to not break.