Is there a way to handmake alphabet pasta?
That's the exact way alphabet pasta is made in industries, it is called extrusion (https://en.wikipedia.org/wiki/Food_extrusion)

Considering rheology specifications, I think you can repurpose a clay extruder for that, but not sure if there is an alphabet attachment for the tip. Mind that it is only productive if you are going to make a LOT pasta since you're going to make a lot of the same letter before moving on to the next.

(Clay extruder: https://www.amazon.com/Makins-USA-35055-Professional-Ultimate/dp/B0018BOXWQ/)