I was like this, and so is most of my old friends still to this day. I still snooze and never come in to work at a regular time, but I've never missed a morning meeting when one is planned.
I just scope out my getting ready, the drive in, account for extra traffic and finding parking, and then add an extra 5-10 minutes on top of the worst case time.
I can't remember the last time I was late to anything now, so it's rare enough that it has to be because of a car breakdown or anything else extraordinary.
Everything that involves more people than you are "too important" to be late for if there is a fixed time set.
Getting ready in the morning is a particular challenge because it varies tremendously. Some days I might fuss around with my outfit and makeup for an hour, other days I can get out the door in 15 minutes.
It's not just the time I "feel like" spending, it's time looking for things, time getting distracted... and time just badly planned (I think I am so early, when I'm not, because I plan these things badly).
(sorry for the short comment but I came to say the same)
EDIT: Removed comment about downvotes.
> "Please don't comment about the voting on comments. It never does any good, and it makes boring reading."
Do you have a bot that looks for downvote keywords?
I've found that exercising control over my body is easy. The body is stupid. It does what I tell it to do. It complains, but it will only fight back when it absolutely cannot physically perform the task.
Not so much with my brain. The brain is smart. It fights back. I can look directly at a (digital) clock, and my brain can refuse to process the time on it.
I can dig around and produce piles of evidence of all the different ways I tried to fix this, all the different treatments I sought, how much sincere effort I put in, and a complete lack of results. Don't take executive function for granted.
Also, our lateness usually hurts us far more than others around us. Nothing is "too important" to be late for. And the things that usually make us late aren't generally important. Most of the time, they're complete wastes of time that didn't need to be done at all in the first place.