I tried something else and discovered something that really confuses me. See if this makes any sense to you.
My wife has a laptop running Windows 11. Before I created a new user I decided to to see if the same thing happened on her laptop and discovered that the slideshow setting stayed the same on a second desktop. So then I started looking to see what was different, and when I made the settings the same on my desktop PC the slideshow setting stayed the same on the second desktop. Here is what I discovered.
My desktop PC has two internal disk drives. Drive C: is a 500 GB SSD and Drive D: is a 1 TB hard drive. When I configured my desktop I created a "Users" folder on D: with the same name as the "Users" folder on C: and changed the locations of all of the Windows folders that had the "location" option from C: to D:. My goal was preserve as much available space on the SSD for programs / files that had to install on C:. I used the "mklink" command to move Outlook files to D: and all of this works perfect.
My wife is using the downloaded Alaskan Theme. I downloaded the Alaskan Theme and everything worked, on my desktop. I discovered that I had to change the desktop setting on the second desktop to "slideshow". After changing the setting on both desktops the slideshow worked. and the setting stayed. I then went back to the slideshow folder I had on D: and everything stayed. The path to the the Alaskan Theme is in the "appdata" folder on C:.
Is it possible that when I downloaded the Alaskan Theme a setting was changed that I probably changed when I configured my PC? If this is what happened do you have any idea what was changed?