Hi @Tom_Kutzner welcome to the Forum! Sorry for the trouble, I completely understand what you mean here. A recurring task will also copy the subtasks within it. That said, setting the subtask to recur as well would be redundant and would also clutter your tasks with duplicates.
To simplify your workflow, you can set the recurrence only for the parent task. When it is going to be completed, it will recreate two new subtasks in this new occurrence and you won’t see the previous subtasks completed. You can find more details on this topic here.
I hope this helps, Tom!