Have you noticed that all the examples on Apple's website, on Medium, and by prominent SwiftUI bloggers only use List views for the sidebar(s) and don't have a NavigationStack in the final detail view that they push additional content onto? There's a reason for that, and unfortunately it's not a pleasant one.

If you're looking to build a seemingly simple split-view app with a 1-depth sidebar and an n-depth detail view, using List in the sidebar view is a fine choice. But if you do not want the cookie-cutter look and feel List is not your friend. Unfortunately, NavigationSplitView really, really wants you to use List and if you don't use one then don't you dare try to programmatically push more content onto the detail view's navigation stack.

This split view demo from WWDC looks great, but what if your side-bar UI would look better if it were layed out as a grid?