Android - WindowInsetsController in Fragment destroys the whole view

Question

I have a Fragment for taking a picture and I wanted to have it in full screen mode. Until API 30, I used the flags as described in the official docs here. But after upgrading the version of my project to 30, Android Studio tells that the flag are deprecated. So, I searched a lot and find some SO questions like this one here. Following the answers I changed my code to this:

@Suppress("DEPRECATION")
        @SuppressLint("ObsoleteSdkInt")
        fun setFullscreen(activity: Activity?) {
            activity?.let{
                when {
                    /*I added this case below. And the view looks very weird. Why??*/
                    Build.VERSION.SDK_INT >= 30 -> {
                        it.window.setDecorFitsSystemWindows(false)
                        val controller: WindowInsetsController? = it.window.insetsController
                        controller?.let { insetsController ->
                            insetsController.hide(WindowInsets.Type.statusBars() or WindowInsets.Type.navigationBars())
                            insetsController.systemBarsBehavior = WindowInsetsController.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE
                        }
                    }
                    /*The code below worked for years. Why they change working stuff?*/
                    Build.VERSION.SDK_INT > 10 -> {
                        // Enables regular immersive mode.
                        // For "lean back" mode, remove SYSTEM_UI_FLAG_IMMERSIVE.
                        // Or for "sticky immersive," replace it with SYSTEM_UI_FLAG_IMMERSIVE_STICKY
                        it.window.decorView.systemUiVisibility = (
                                View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
                                        // Set the content to appear under the system bars so that the
                                        // content doesn't resize when the system bars hide and show.
                                        or View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                                        or View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                                        or View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                                        // Hide the nav bar and status bar
                                        or View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
                                        or View.SYSTEM_UI_FLAG_FULLSCREEN
                                        or View.SYSTEM_UI_FLAG_LOW_PROFILE
                                )
                        (it as? AppCompatActivity)?.supportActionBar?.hide()
                    }
                    else -> {
                        it.window
                                .setFlags(
                                        WindowManager.LayoutParams.FLAG_FULLSCREEN,
                                        WindowManager.LayoutParams.FLAG_FULLSCREEN
                                )
                    }
                }
            }
        }

In the fragment, I call this method like this:

override fun onCreateView(
            inflater: LayoutInflater, container: ViewGroup?,
            savedInstanceState: Bundle?
    ): View? {
        // some code ...
        // bla bla etc.

        setFullscreen(activity)
 
        // .. and so on


}

Here is a demo:

As you can see, the button on top is not reachable for the user and the bottom of the view is also white. I hope someone can help.