Yes, you need a MacOS computer to compile for MacOS and iOS, as per the documentation for MacOS and iOS. You may be able to use a virtual machine to work around the issue, but that has its own issues with Apple and the agreements for MacOS (last I knew).
To export a Godot project for MacOS, you do NOT need a Apple computer, you can use one of the prebuilt templates included with the official Godot releases. You do need a MacOS computer to export a Godot project to iOS though.
