In the Workspace Setup with Show Tabs selected you can add a new tab, but I think only one TAB at the time. It’s the same way as Sibelius. But is it also possible to select all the instruments at once so that you create all the tabs in one click. That would be great. I like to switch fast between the different parts.
Be aware that having all your instruments open as Tabs may slow Dorico’s responsiveness.
There are great keyboard shortcuts to display different layouts, very useful.