My set-up is:
Notion as my planner/life management system (bit of faffing to get it set up but once you do - game changer)
ROUTINES - hate them but need them, every evening before bed I shower, skincare, yoga, journal, teeth. Now it's like a Pavlovian thing and I am better at general washing/self care.
Accept the 'nope'. Redirect energy when the brain just isn't braining: can't do X? Okay, fine. Stop trying, cos shame and frustration just makes it worse, redirect, do something else, get your dopamine fix and see if that helps break the deadlock.
Actually being hydrated - 2.5 litres a day or my brain jams up like an old printer.
Movement - hate 'exercising' but frequently walk round my house dictating notes into my phone for work, then when I sit back down I'm already locked into the task cos the movement helps. If I'm fuzzy and can't make myself do something, full-body-shake-out and a bit of light screeching like a pterodactyl helps snap me out of it.
Dunk face in cold water. Supposedly good for calming anxiety, and I find it helps me stop the 'should be doing X / not doing X so anxious / too anxious to do X' spiral.
Pomodoro. But don't beat yourself up if you ignore it sometimes - all my ADHD tools are 'if they're working good, if they're not it's okay'.
Visibility. Something I need to do regularly? GOTTA be able to see it. Bin collection schedule taped to a cupboard I see every day, or the bins do not exist to me. Skincare lives in a box on my desk. My calendar is on my phone homescreen in a widget, my desktop as a widget, and hung up in a paper version on the wall. Need to remember to do X tomorrow? Put the thing, or a note about the thing, or a letter relating to the thing, or whatever, ON THE DINING ROOM TABLE RIGHT NOW BEFORE IT CEASES TO EXIST IN YOUR MIND. Open wardrobes, so I can see when I have no clothes and it's not a fun surprise to discover I have no clean jeans 5 minutes before I need to leave the house. Put my car keys by the thing I need for the next day. And so on..
Tile trackers. I know, you know, we all know I'm gonna lose my keys, the TV remote, and my favourite water bottle 402383892 times a week. Tile tracker that shit. Worth every penny.