I never used the desktop app so I have no idea what could go wrong, any error message or anything on your side?
Sorry, should have specified
Your build isn't good for offline use. Index.html is trying to load a local js file, which isn't allowed by browsers (including itch.io's desktop app, which it launches the game with)
I'm away from my pc atm, but you'll see the error if you try running the game from itchio desktop app