That 80/20 idea is one of the worst startup killers I know. If you were my boss I'd be putting on my parachute and heading for the airstairs and expecting to see a plume of smoke wherever you impact.
You don't have to do 100% of what anybody might want, but you have to accomplish 100% of a minimal viable product and some of that is grindy and unglamorous. People who set out to do the easy 80% just don't get to the MVP.
I like Covey's quadrant model
https://purdue.edu/asc/handouts_pdf/Coveys%204%20Quadrants.p...
my take is 80/20 managers inevitably let "important but not urgent" work be undone. See also