Mimic Single App Mode on Desktop?

MacOS has always had a secret “single application” mode that can be enabled via a terminal command, giving you one application per workspace, a bit like iOS, but this is based on launching apps from the dock. I’m looking for something that would work no matter how you launch an app. Are there any tools for macos which will do this?

Try Amethyst with the Fullscreen layout.

Hmm. Thanks, but that doesn’t seem to use spaces?

Nope.

It will automatically resize every app to be the size of your screen, thus the active app will always cover the others.

Every app will stay in the same space unless you manually move it to another space. So Mission Control and every other “regular window” feature will work fine with them.

You won’t see your wallpaper much, though.

AppSwitcher can do this. It sits in the menu bar and automatically hides all apps except the front-most one.

There’s an easy toggle to turn it off if you need to disable it for a time.