M4 Pro user here. "Full screen" on Mac means the current App window becomes a new temporary virtual desktop, which is placed after your normal virtual desktops. It also turns off the status bar / app menu, even though you don't get that screen space back because of the camera notch.

How many virtual desktops you have and which one is active is display-specific. So if you like multitasking, I hope you're good at remembering their order and purpose and don't mind performing the same gesture repeatedly to get back to your app.

You might just want to maximize your app window instead. Though you do need third-party software to do that properly.

I wish I was kidding about any of this.

I don't even know whether I understand I just hear MacOS users griping about fullscreen, and a quick google gave quite recent results. Especially with fullscreen being incompatible with other windows on top (each fullscreen window necessary is on its own workspace) which would be highly annoying in Blender. You can configure blender to have file open dialogues, render results etc. in its main window, but certain stuff like preferences always open a second one.