You can achieve this functionality today in Plex. Here’s an example for a movies-type library.
- Select the Library view for the library.
- View the library by Movies, and sort “By Date Added.”
- Change “All” to “Advanced Filters.”
- Select the “Unwatched” filter and set it to “is true.”
- Optionally, add other relevant filters and/or set an item limit.
It should end up looking something like this:

- On the right side of the page, select Save As → Save as Smart Collection (it’s important that you select the Save as Smart Collection option). Then, give the collection a meaningful name (I suggest “Recently Added and Unwatched Movies”).

View your movies library by Collections and find the one you just created. Click the vertical ellipsis in the bottom-right of its poster and select Visible On → Home (and/or Library/Friends’ Library).

The collection will now appear as a hub on your home screen just like any other hub. Its order and visibility can be managed in the normal way, via Settings → [Server Name] → Libraries → Manage Recommendations.
The collection is dynamic and will update whenever the filter criteria are met/unmet.
Optionally, you can now disable Plex’s built-in Recently Added for your movie libraries.