It looks like Monterey won't play my game. I have not made any progress toward finding out what they did. I'm also suspicious that if I find a way to fix this, it will stop working again for new reasons under Ventura, and so on.
I have read that the notifications system (that can't be turned off anymore) may be taking focus away from the app, and getting it back is a well kept secret from us dirty indies. Try clicking in and out, try command-tab, try minimizing and restoring. If something helps, please let us know. I would be delighted to find it was a mistake on my part.
PS: It runs under wine, even on Monterey. I have no idea how that works since the windows version isn't codesigned.