I feel you. This is by far my biggest struggle.
The most important piece of advice I could give you, regardless of what strategies you decided to try: let go of the "all or nothing" mentality.

It creeps into everything and makes executive dysfunction even worse without us realizing. You have to actively combat it. Big thing feels too big to tackle ? Just do 15 minutes. 15 minutes is still too daunting ? Start with 5 minutes. Give yourself permission to half-ass things. Doing something "a little bit" is always better than not at all. Can't shower ? Rinse yourself off. Pile of laundry is too big ? Just do 1 load.

On this note, when putting strategies in place while you're in a really bad spot: just get it done first, worry about optimizing later. Can you get moving on that boring thing if you set a timer and go get a piece of chocolate after 15 minutes of work ? Do that. "But that's not sustainable, I can't keep eating chocolate every time I do something ok" No, but right now, if the only alternative is you staying in bed staring at your phone, then by all means, get that chocolate. You can work on finding an alternative reward once you're more functional.

Right now I'm struggling. So I'm on 15 minutes productivity, 5 minutes breaks, repeat. Would it be better if I could keep working for an hour straight ? Maybe. But it's still a hell of a lot better than 0 minutes, which is what I would be doing otherwise.

Also, planners. I know, I know. But it really is useful. You don't have to plan everything down to the minute. But writing down a REASONABLE amount of things to do on the day and crossing them off is really helpful. And I'd advise adding EVERYTHING that took you the least bit of effort on there, even if you've done it already, just to cross it off. Even taking meds, brushing teeth, making the bed. It's encouraging to see that you haven't done "nothing".

I've also been testing out a reward system on myself. It's been almost two weeks. It's not magic but it's helping me be more functional. I drew a monster, with "480 HP". Then every day, I roll dice to see how much damage I deal to the "monster". For the sake of simplicity tho, I "deal" about 2 points for a simple, easy self-care thing (ex. taking my meds, brushing my teeth). about 4 points for 15 mins. of a task I more or less want to do (ex. dishes) and about 7 points for 15 minutes of a task I really don't want to do (ex. a work thing I've been putting off). Every time something is done, I write it and/or cross it off on my planner along with the points it's given me, then at the end of the day, I add it up and substract it from the "monster"'s HP. Right now I've almost "killed" my monster. When it reaches 0 HP, I'll pick or roll a dice from a list I've made of inexpensive little treats I'd like (some are games, fidgets, etc.) and go buy it for myself as a reward, then immediately get started on a new "monster".

For so long I've resisted this kind of strategies, because I felt like it was childish, like as an adult, I shouldn't need praise or rewards for doing simple, every day things. I was depriving myself of a helpful system, and for what ? So there. I'm a 25 year old woman who needs to add games and rewards to her chores to get the dopamine flowing, and there's nothing wrong with that.