I’m publishing my game in Steam/MacOSX for the first time, and I’m not sure what to do because the lack of an official guide to that specific case.
I’ve developed for iOS, I’m familiarized with the Apple Developer Program, but I’m not sure if the steps for MacOSX (AND Steam) are the same or not.
Do I need to create a provisioning profile (or any other Apple Developer stuff) before making the build, specially if the game is not for the Mac Store, but Steam instead?
No need. Steam is the gateway to approving the apps for running on each system. Of the Steam games I currently have installed on my laptop, none of them have any signatures at all, but they run without warnings. Just export from Unity and follow whatever the steps are for Steam submissions.
If you’re using Steam you’re embedding that the Steam way, presumably? If you’re implementing ANY of that via Apple’s mechanisms you can’t distribute it via Steam, only the Mac App Store. If you want both you need two different projects.