Fullscreen is easy, right? Unity handles it for you, and you can always just set Screen.fullScreen, right?
Well, yes and no. There are some weird quirks in Unity’s fullscreen implementation, at least on Mac. I haven’t verified whether these issues also exist on Windows, but the workarounds I came up with don’t break anything on Windows, so they’re safe to use (as far as I’m aware).

Unity has some issues with fullscreen
If you have any questions about this article or about Unity development, you can find me in my discord server : https://discord.gg/zeCKc8SnHs
The problem
Let’s start with a blank Unity project. I set it to 2D (but the issue applies to 3D as well), and set the camera to clear to a nice solid color.