Aside from getting treatment, what’s helped me:

• know that you’re incapable of forming habits. You have to choose to do the thing every time.
• Trick yourself into hyperfixation if you can. It’s a superpower, if you can aim it in a useful direction. Find something gratifying or satisfying about the task to focus on. Sometimes watching the todo list get smaller or the inbox get cleared out does it for me.
• This one’s hard to describe, but sometimes you have to realize that the hyperfixation easy-mode motivation isn’t coming and you’ll have to draw motivation from somewhere else inside yourself. Sometimes just getting over the initial jump of starting a task makes the rest of it flow naturally.
• Break big problems into little problems.
• Simplify your life as much as possible. You only have so many executive function tokens every day, don’t waste them.
• have a todo list. Don’t make it complicated. If possible, just do the thing immediately instead of putting it on the list.
• Get enough sleep. This is not optional.
• Exercise, specifically some kind of cardio. 30 minutes above about 120bpm, 3 times per week. There are studies, it makes a big difference in a million ways.
• Give yourself grace. You’re playing on hard mode, don’t compare yourself to neurotypical people.

Edit: also it’s not laziness, not really. Lazy people are comfortable with it.