This is so me…i am notoriously late. Or way too early. Before retiring I often met with clients at their office, or occasionally at lunch. After another infamous missed lunch with a client who waited over an hour, Client cancelled our $20,000 retainer (1992 Dollars) In desparation i finally delegated this responsibility to my assistant (she was really my neuro normal timeliness manager by then) It worked.
15 years later when retirement set in, I was at a loss again. My Ibook was not helpful. About 4 years ago i bought my first Ipad. Gradually the use of the clock functions and reminders and the calendar have become my new replacement. Two ipads are used with twice the reliability as they actually interupt my hyperfocus long enough to work. Its not perfect but it is a heck of lot better than before.
Until I shut them both off .