You are technically correct, except that you have to jump through hoops to run an unsigned application (https://support.apple.com/guide/mac-help/open-a-mac-app-from...), which for the normal user is tantamount to not being able to run the game.

Not anymore thanks to signature requirements. You need to be a registered developer and notarize your binaries.

Not actually required. Strongly suggested, but not required.