I've spent years working on building up my sleep duration and this year am doing pretty well on it. This interesting 9 minute video by researcher Nessy Hill also mentions the importance of other factors such as sleep regularity. The Formula to Stop Feeling Tired.

Recent evidence indicates that sleep regularity, defined as the day-to-day consistency of sleep–wake timing, is a stronger predictor of some health outcomes than average sleep duration.

Via: Sleep regularity is a stronger predictor of mortality risk than sleep duration: A prospective cohort study | SLEEP | Oxford Academic.