Either this game doesn't like being run headless because Pygame, or something is wrong with the build.
I ran pip install -r requirements.txt --break-system-packages (which installed system packages in the user store rather than site packages).
Then pyinstaller on zombowl.spec.
The build appears successful. Now, I run in the Mate terminal ./zombowl.
I get the dreaded no available displays error. Even though hdmi-force-hotplug is set to 1 in the BTSpeak's /bott/config.txt. Does Pygame not work with that means of providing a dumby visual output?