“Just sit down and get the work done or we’ll take away your phone” REALLY doesn’t work.
A friend with ADHD and EF deficits explained it to me like this-
“It’s like that classic recipe “how do you make turtle soup?” which says “first go get a turtle and then make the soup”.
To someone with EF, the entire world is asking for turtle soup, and nobody will help you figure out “where do a I find a turtle, what kind of turtle, how do I catch a turtle, once I catch it, how long do I wait before killing it for the soup? etc.” Meanwhile, everyone around you is serving turtle soup, having somehow figured out where to find a turtle.