[OP’s workaround] Creating a “Smart Collection” and using “Settings > Manage > Libraries screen” to add, remove, and order the collections did exactly what I wanted.
[mod-edit: clarification that the OP’s “solution” is a valid workaround while others are still hoping for the requested feature suggestion to be implemented → toggling of played/unplayed items vs. only showing one or the other with a published collection]
On our Roku TV, the Plex app nicely shows a “Recently Added” list for our Movies and TV libraries. Unfortunately, it displays Watched content in these list which is frustrating, because once watched, we don’t need to see them. We can certainly drill down into the library and filter on Unwatched only, but being able to filter out Watched content by default on the Home screen would make the experience so much cleaner (for us, anyway.)
This is a feature that’s been requested for a while, but for some reason falls on deaf ears.
(Plex user for over 5 years, and we bought a Plex Pass last year.)