When I create a new project on Make Code I see a Block option and a JavaScript option. Is it possible to “grab” the generated JavaScript and execute on a RaspberryPi? Do I need additional supporting libraries?
How to run MakeCode generated JavaScript code on RaspberryPi
You need a specific firmware for the Raspberry Pi Zero to execute the .UF2 file that Arcade will be running.
Follow the Adafruit guide on how to setup on RPI0 -> https://learn.adafruit.com/makecode-arcade-with-raspberry-pi-zero/firmware
OP is asking about running the JavaScript, not the .UF2 file.
This is not a supported scenario at the moment. You can share you program and load it in the raspberry pi browser.