Xfce's Panel Profiles app can rearrange the desktop into a dozen alternative layouts, including macOS and Unity styles, but getting every layout working properly still takes some manual tinkering, according to a two-part feature in The Register.
In the Unity layout, the global menu is immediately followed by the status icons, when they ought to be over on the right. The fix involves adding a separator to the top panel immediately after the appmenu and setting it to Transparent and Expand. For the Cupertino (Mac-style) layout, the strangely aligned menu can be corrected by going into the top panel's preferences, finding the AppMenu plugin, and unchecking 'Expand'.
Both layouts use Xfce's default Window Buttons app-switcher in the dock-style panel, which does not support pinning apps. The Docklike Taskbar plugin combines pinned launchers and running-app indicators. It can be installed with 'sudo apt install -y xfce4-docklike-plugin', then added to the panel after removing the Window Buttons plugin. The plugin can show a colored bar or macOS-style dots next to running apps, and optionally preview thumbnails.
Getting applications to use the global menu requires additional configuration, as described on the Vala panel appmenu project page on GitLab. After following the instructions, all the bundled apps tested that had menu bars used the global menu. Some things do not, such as the Task Manager. Mozilla Firefox no longer supports Unity's global menus, but Waterfox still does.