SwiftUI navigation unfortunately seems to still be quite limited. There was an early discussion on this forum that still appears to apply today: Deep nested navigation
The default binding behavior still seems to clash with trying to drive navigation from state (and differs across iPhone/iPad), and deep-linking doesn't seem possible without some pretty big manual workarounds. We were hoping some of these issues would be resolved in this series of betas, but so far that doesn't seem to be the case.
Folks appear to have been taking matters into their own hands in the meantime: GitHub - matteopuc/swiftui-navigation-stack: An alternative SwiftUI NavigationView implementing classic stack-based navigation giving also some more control on animations and programmatic navigation.