I really wish this was do-able:
The screensaver function would let us choose portrait or landscape style photos.

I have two monitors attached to my PC. Orientation of the left one is landscape and right one is portrait (vertical). Right now I can set display fusion to show screensaver using my photos. I have thousands of photos in both landscape and portrait formats. I would love to see my photos which were shot in portrait format on the right side monitor and the photos which were shot in landscape format on my left side monitor.

This information is already there in the photos (EXIF). I really wish there was a screensaver which could read the EXIF, determine if the photo is portrait/landscape style and display the style I want on the right/left monitor respectively.

Wishing for too much, am I?