Thread as a somatic therapist who has worked with a lot of people who struggle with executive functioning around procrastination.
The short answer is you have to keep a stream of dopamine going the whole time because that’s what your brain is low on and needs to do the things
One time a therapist was like “give yourself a reward for completing a task” and I was like “or I could just give myself the reward anyway and not do the annoying boring daunting task” and she was like… oh.