One design sample I admired is a double navigation bar on the left side. If you click on a button on the left, it has two functions. The first is that it controls the second navigation pane, which, when clicked, alternates new content that may serve as more navigation for displaying some content. The second function of the first navigation bar is to load a complete new route that loads only in a section such as an iframe area.
How would you design the best solution when you click on a navigation bar button that loads a new route? The second navigation bar remains on the loaded object and is not loaded into the status of a standard navigation bar, as is the case with every new route.
So if I click on an option that changes the second navigation bar and then click on a new route, only the new route will be displayed and the second navigation bar will not be affected.