If you’re spending time looking and wondering that you always need to go to the app switcher to go the Settings from the Unified Interface, you need to do the following –

Once you are in the Unified Interface, click on the Gear icon next to the help icon on top-right corner as shown below and click Advanced Settings –

Right on the next tab, Settings with the classic UI is shown –

And there’s nothing else on that SiteMap.

And that’s it! 🙂