Trying to sprinkle the glitter using the gamepad with Y won't work. So it's pretty unplayable for me.
Gamepad: Microsoft XBox wireless (windows ediition).
OS: macOS Catalina
I'm sorry that you're unable to activate Misfortune's glitter sprinkling with the "Y" key on your MS XBox wireless controller.
I don't have a Mac computer, nor a XBox Wireless controller to test your configuration with. I'll ask the rest of the developer team if they have a configuration of hardware like yours to test with and post again later.
In the meantime, I offer these suggestions (which may or may not be helpful to you):
Reboot your Mac if you haven't done so since you installed the game on it and try again to see if the situation improves.
Can you use your XBox controller in wired mode to play? This site: https://www.gamespot.com/articles/xbox-one-controller-is-both-wired-and-wireless/1100-6409392
/ seems to indicate that is possible, but I'm not sure if your controller is exactly the same as shown in this article. I also understand that playing with a cable may not suit your preferences.
Can you disconnect and reconnect your controller and then try again? May not help, but it might be quick to try.
If you have any other devices (that aren't critical to running your Mac like a keyboard or wireless card) connected to USB or via wireless, can you try to disconnect them to see if that helps. This is Windows advice, but if its convenient to try for you, it might rule out a device conflict. Although why only one key doesn't work is strange.
On the Windows version of the program setting the Controller in the "Options"/Input menu to "Gamepad" still allows you to use keyboard commands. Can you try the "F" key on your Mac keyboard to sprinkle glitter? Again, I realize this may not suit your preference, but it may work while we see if we can test your configuration and post again.
If that doesn't work, the option to play with Keyboard only ("F" key to sprinkle glitter) or Mouse + Keyboard ("F" key or "primary mouse click" on Misfortune to sprinkle glitter will then work) is another work-around while we investigate.
It's difficult to further troubleshoot without having your same configuration to test with, but I'll post again as soon as possible about whether we'll be able to suggest something else.
I'm sorry for the trouble you're having.