Migrating from NavigationViews to NavigationSplitView, setting detail column from within?

I am in the process of migrating from NavigationView as a root to NavigationSplitView. My model supports various different objects, and what would fit into the content column varies from a list, to a TabView with a list within. This particular example (which I refer to from here on,) the lists hold two different objects within the model. The layout looked like this:

NavigationView  // Used for sidebar, would now be NavigationSplitView(sidebar:content:detail)
- NavigationLink -> TabView
    -> List(objectA)
        -> Object-Specific DetailView
    -> List(objectB)
        -> Object-Specific DetailView
- NavigationLink -> List(objectC)
    -> Object-Specific DetailView
- and more like the above

As it stood, there was no "third column" functionality, but with the new API I am seeking to achieve this.

I am however, hung up on how to change the detail pane properly from within these sub-views. Am I needing to pass the various objects up to the struct housing the root NavigationSplitView?

I don't currently use anything like Scene Storage, or other frameworks currently besides using CoreData with CloudKit. I know there's lots I need to be reading, is there somewhere I can go that really goes through UI Navigation and Elements?

The end goal is a three-column application (including the sidebar as the first) that dynamically changes the content column from the definition of NavigationSplitView, but with a clear solution to changing the detail column to display different views that are specific to each object.

Nesting a NavigationStack would come close if it could adjust the parent NavigationSplitView's detail column?