FlashSpace

FlashSpace replaces macOS Spaces with its own workspaces. You assign apps to a workspace and a display, give it a hotkey, and switching shows those apps while hiding everything else on that display, without the system's sliding animation. Each display switches independently, and workspaces can also follow the displays their apps are on.

Around that core it adds an Option-Tab workspace switcher, a grid preview of all workspaces, hotkeys for moving focus between windows, floating apps that stay visible everywhere, profiles, trackpad gestures and a configurable menu bar label. Settings can be edited in the app or in JSON, YAML or TOML files, and a command-line tool and SketchyBar hooks allow scripting.

It needs macOS 14 or later. The project asks you to keep all apps on one native Space per display and to leave "Displays have separate Spaces" turned on in Desktop & Dock settings. Picture-in-Picture handling is experimental.