“GetSupportFragmentManager устарел” Ответ

GetSupportFragmentManager устарел

Right now, in Kotlin I use
val fragmentManager = this@className.parentFragmentManager

or (prefer this one)
val fragmentManager = this@className.childFragmentManager

well if you still use Java I think the code is
FragmentManager manager = this.getParentFragmentManager();

Hope my answer can solve the task.
I recommended you to use Navigation now