Hi,
Yes, you can run the same playlist on both screens, but keep in mind that the aspect ratios of your screens (16:9 for the 4K screen and 9:16 for the portrait screen) are different.
On the 16:9 screen, the content will fit naturally, filling the entire screen without issues.
On the 9:16 portrait screen, content with a 16:9 aspect ratio (like videos) will appear in its correct proportions but won’t fill the entire screen. Instead, you’ll see black bars above/below the video, as shown in the illustration.
If your goal is to display the same playlist without adjustments, this setup will work but with these visual limitations on the portrait screen.
image.png
What you can do in this case is to use Playlist in Playlist functionality.
https://playsignage.com/support/playlist-in-playlist/
You can find plugins that you could use on portrait screens unused area here:
https://playsignage.com/plugins/