If you're asking how people solve problems with systems they know from head to toe, with which they have worked for ages and they know common issue types, and p

If you're asking how people solve problems with systems they know from head to toe, with which they have worked for ages and they know common issue types, and procedures how to diagnose and debug by endless repetition, you're right, they don't need to sleep on it, they just do it by muscle memory. That's not unlike math olympiad competitors or competitive coders who by repetition generate a skill for those types of problems exactly.