I'm not sure most NEMA 17 motors are rated for 24V. Also, this thread is about designing an extruder, not buying a ready made solution. I'm not really planning to design and build an affordable printer just to buy an extruder to double the price.
Also, I get that a larger nozzle lets you pump more filament through (since less force is needed for the same volumetric flow), but to be clear, I'm asking for any given nozzle, with a heating cartridge that can supply sufficient heat, where the only thing changed is if the extruder is geared or not, would the geared or non geared extruder be able to push filament faster?