They still need tasks broken down into smaller steps with clear instructions and reminders. A task with several/many steps, or one with many possible ways to tackle it, is nearly impossible to complete without guidance.
My child, and many autistic people, have serious issues with executive function. If you were faced with cleaning a messy room, you'd pick up items from the floor, put them where they belong, wipe up that spill you noticed while tidying, vacuum the rug once it's cleared, run a duster over the surfaces, straighten the crooked picture on the wall, etc.
A person with executive function problems will literally struggle to know where to begin. Once they do begin, they may not be able to do things in the "logical" order (i.e. pick up toys from the rug before vacuuming), they may be distracted by other things that come up (i.e. you've picked up half the toys when you notice the spill, so you go get a towel to wipe up the spill but on the way you see a boot left in the middle of the hallway so you pick that up to put it away but then there's a knock on the door so you answer it, still holding the boot, sign for the package, go put the package on the kitchen counter, realize you're thirsty so you grab a quick drink of water, and then you're standing there with a boot in your hand and the original messy room a distant memory), or they may just get overwhelmed by the task and shut down.
If a person is already dysregulated in terms of sensory needs, executive functioning is impossible. It's like trying to do trigonometry with someone screaming in your ear.