GridLayoutManager with 'onLayoutCompleted' callback. You can use this to execute code after the layout has finished drawing on the screen. You can also use 'isLastItemCompletelyVisible' to enable/disable the nested scrolling, for a better experience with Appbars who have 'appbar_scrolling_view_behavior"' set.

NotifyingGridLayoutManager.kt

class NotifyingGridLayoutManager(context: Context?) : GridLayoutManager(context, 1) {
    var onLayoutCompleteCallback: OnLayoutCompleteCallback? = null

    override fun onLayoutCompleted(state: RecyclerView.State?) {
        super.onLayoutCompleted(state)
        onLayoutCompleteCallback?.onLayoutComplete()
    }

    fun isLastItemCompletelyVisible() = findLastCompletelyVisibleItemPosition() == itemCount - 1
}

NotifyingGridLayoutManagerExample.kt

override fun onCreateView(...): View? {
    ...
    val layout = NotifyingGridLayoutManager(context)
    layout.spanCount = 2
    layout.onLayoutCompleteCallback = onLayoutCompleted(layout)
    ...
}

// Turns off nested scrolling if the items in RecyclerView are all visible.
// This way, your Appbar/BottomNavigation/Fab won't scroll away if it is not needed.
private fun onLayoutCompleted(layout: NotifyingGridLayoutManager): OnLayoutCompleteCallback? {
    return object : OnLayoutCompleteCallback {
        override fun onLayoutComplete() {
            recyclerView.isNestedScrollingEnabled = !(layout.isLastItemCompletelyVisible())
        }
    }
}

OnLayoutCompleteCallback.kt

interface OnLayoutCompleteCallback {
    fun onLayoutComplete()
}