I have found the best way to cope is to surround yourself with people that understand and help you out when you fall short. Easier said than done for sure and it hasn’t always been that way for me but at this point I have a bunch of ADHD friends so they all get it, and my wife saves me usually, she is the best at that hah. Other than that I have been just leaning into it lately, for example find a job that has a lot of tasks that work well with your brain, choose wisely.
I also treat my attention as a privilege that I can give people and not something someone can demand. I don’t phrase it that way to be egotistical, it’s just that my attention and focus is fleeting sometimes as it is so I need to defend it in that way to have any at all. This is also harder said than done but it’s also not too difficult, most people are understanding when you say “can I get back to you in 30 min when I’m done with I am doing” or “let’s put time on the calendar to work on that tomorrow” it turns out.
Along this same line I also treat notifications everywhere as an opt-in activity, everything gets denied and I only let the most important ones through focus modes (I have an iPhone) that I actually need to receive and this includes all phone calls on all mediums. The only people that get let through focus modes are those that understand the gravity of interruptions on my brain (well and my parents because they are great hah).
Well that was longer than I thought it would be but the short version is that you have to try to construct a situation for yourself that works with your brain and not against it, and it’s a long journey but you have to keep iterating on it like you have been.