Adding a user preference for this is not in our plans at this time, nor is making a separate theme component. The usage and feedback of unified new so far hasn’t justified a strong need for it.
But as I said, it should be easy enough to make a theme component (or alter an existing theme) that modifies labels in the UI to split the new/unread count again, and if you need core plugin APIs available for this I will be more than happy to add them 