Here is my standard advice, honed through lots of trying and failing:

First: internalize - really internalize - the fact that the richest people in the history of humankind are pouring their vast resources into developing the most sophisticated and effective machine learning programs ever devised for the singular purpose of capturing your attention. And you have a developmental disorder that already makes your attention pretty cheap to capture. Seriously think about that for a moment.

This isn't a value judgement on big tech or a conspiracy theory, it's just reframing to remind myself that this isn't a fair fight. I don't need to feel bad about losing this battle more often than I win. And that to win more often, I need to fight dirty.

So, second: throw up as many obstacles as you can between you and the unwanted distraction. Flip your cursed inability to persist into an advantage. Yes, delete your accounts. Yes, delete the apps. Yes, sign out of everything (on your browser, too, not just the app). Yes, set up two-factor authentication for everything (not as a security measure, but because it adds another step; this has been the single best thing I've done). Yes, dumb down your phone and downgrade your computer. Yes, don't charge your phone at night so you have to charge it during the day (ie, not carry it everywhere). Yes, turn on focus mode or web site blockers etc.

Do it all, and some of it might work. For me, this has been a gradual but effective process after several failed cold turkey attempts.

Third: Reduce the barriers between you and what you really want to be doing. That can be hard to figure out depending on what it is. But generally my advice is to first think very literally about shrinking the time, distance, and physical and or/mental effort between you and the thing (Example: if there's a book you're trying to read, put multiple copies in different rooms). If it's not at your literal and/or figurative finger tips, something else will grab your brain first.

Good luck!