A QStackedWidget works like a book. You have pages with your content. You can flip these pages to change your widget inplace (without opening another window or something else).
So one possibility is to put one of each QTabWidget (each with a different tabBar position) on a page of a QStackedWidget. You could flip the pages by clicking a dummy tab on each tabBar or you use a button to go to the next page. I know, this is not exactly what the widget in your image looks like :)
Haven't used QT much
If you want a widget, that looks exactly like the one shown above, you could still try to subclass and create your own, custom TabWidget, but I fear, that it might be a little too challenging.
Here's all you need to know about QStackedWidget (https://doc.qt.io/qt-5/qstackedwidget.html#details)