I learned to effectively use the experience as infinite fuel for doing anything. But it's also as if my internal presence changed, there is no right word but let's say "expanded", could have something to do with mental time, I feel extremely old (which isn't negative, it just is). I'm able to complete the hardest possible tasks at work and there's no limit to that, I just keep going, except I don't overdo stuff because if I overdo work every day (e.g. 12h of heavy mental work every day) I get brain fog for up to a week (it makes me less capable when doing heavy mental work, and also can decrease short-term memory retention) it's like an inflamed muscle (when it happens it's best to start using different type of intelligence, e.g. if problem solving was overused, then doing something creative like a design or writing).
And if I'm overdoing my training every day, after given enough time I get injured or too inflamed therefore unable to train for some time which is why I split my training properly and train to the maximum physical capacity at maximal time duration up to a point where it doesn't cause any issues because it's my priority that I can always keep going, the same principle applies for work.