I’m also stripping the screw top at the base trying to get it off. A hole in the side of the shaft would give much better leverage in a system that self tightens than a naff old screw and a hole in the plastic base that doesn’t let a screwdriver through,
Found a solution. Remove the base plate (4 screws), wiggle the plastic fan off the shaft of the screw head (now stripped because it is very difficult to get effective torque with that much surface area to screwdriver surface area plus really soft metal) and grip the ribbed shaft with pliers while turning the plastic base gear up top.
Really Nutribullet a loosening direction arrow (because it is opposite what is usual and difficult to deduce from mirror image videos) and a hole in the shaft to ease turning would make changing this so much easier and so much less landfill.