There's a question of cost. Maybe you can be on time for a flight once in a while, but it costs you so much X (time, mental energy, money, whatever) that the same strategies would not help in day-to-day schedules. Ask someone with DSPS, for example.
You completely misunderstand how executive functioning deficiency works, it appears. While this was written by a person with chronic pain issues (you might not be aware of!), it applies to many other (often also invisible) disabilities: https://butyoudontlooksick.com/articles/written-by-christine....
"Just leave earlier" is about as useful an advice as "grow a new hand."