Hey thanks for giving it a try!
Apparently Godot doesn't currently play nice with web builds and Macs. I added a downloadable version that is built for macOS if you would like to try that, but unfortunately I don't have a way to test it, and I don't have an Apple Developer ID so Gatekeeper may block it.
(https://docs.godotengine.org/en/stable/tutorials/export/running_on_macos.html#ap...) - looks like this is the expected behavior