[versions]
composeBom = "2024.10.01"
material3AdaptiveNavSuite = "1.3.1"
material3Adaptive = "1.0.0"

[libraries]
androidx-material3-adaptive-navigation-suite =
 { module = "androidx.compose.material3:material3-adaptive-navigation-suite",
 version.ref = "material3AdaptiveNavSuite" }
androidx-material3-adaptive-layout =
 { module = "androidx.compose.material3.adaptive:adaptive-layout",
 version.ref = "material3Adaptive" }
androidx-material3-adaptive-navigation =
 { module = "androidx.compose.material3.adaptive:adaptive-navigation",
 version.ref = "material3Adaptive" }

Currently, NavigationSuiteScaffoldDefaults.calculateFromAdaptiveInfo() returns NavigationSuiteType.NavigationBar for most smartphones in landscape mode, because while windowPosture.isTabletop is false, windowSizeClass.windowHeightSizeClass == WindowHeightSizeClass.COMPACT is usually true.

The navigation bar consumes a lot of valuable screen real estate, where as a navigation rail would require much less. See screenshots for comparison.

Currently apps can do something like this:

val adaptiveInfo = currentWindowAdaptiveInfo()
val customNavSuiteType = with(adaptiveInfo.windowSizeClass) {
    if (windowWidthSizeClass != WindowWidthSizeClass.COMPACT &&
        windowHeightSizeClass == WindowHeightSizeClass.COMPACT) {
        NavigationSuiteType.NavigationRail
    } else {
        NavigationSuiteScaffoldDefaults.calculateFromAdaptiveInfo(
            adaptiveInfo
        )
    }
}
NavigationSuiteScaffold(layoutType = customNavSuiteType, navigationSuiteItems = {

However, I suggest updating the decision logic in calculateFromAdaptiveInfo() as shown above.