Hi Devlin,
It seems if I walk away from my computer, usually the lock screen slideshow will automatically kick in. Most of the time it functions are normal but sometimes it just does not.
Meaning it gets stuck on one of the windows photos in the lock screen that's under the "picture" option in the lock screen settings.
Also the preview window for background shows a preview of the folder I am using as you can see below:

However when I am on the lock screen option, it shows a preview of one of the photos from the picture option in the dropdown even though slideshow IS selected. It used to show a preview of one of the images in whatever folder I am using for the slideshow
like below:

Also upon locking the computer manually pressing the windows key plus the L button, it gets stuck on this specific blue photo from the "picture" option in the dropdown and the CLOCK AND DATE are gone from the screen. It just shows this photo and nothing
else. It does the same thing if I manually select a different photo from the windows picture drop down and set it back to slideshow like below:
I chose a new photo from the "picture" dropdown

Then I rechose slideshow from the dropdown and its still showing the windows picture and NOT one of the slideshow images. When I lock the computer manually, it shows this rock photo below.

When I walk away from my computer to let it idle and the lock screen slideshow to begin on its own, it shows the above photo (even though on slideshow) and no clock and date show. Then when I click to login, you can see one of my slideshow photos for a split
second until it goes back to this photo again. If I restart my computer, it fixes temporarily until it does this process again.
When it does work as normal, you see this photo for about 15-20 seconds and THEN the slideshow starts but its random. Sometimes it works and sometimes it doesn't. You guys are more than welcome to contact me and share my screen to see these issues if you
like. I am at a total loss as to why its behaving like this, especially with a fresh copy of windows. It doesn't matter what folder I use, same issue. Shows the windows photo, click it to login and I see one of my photos for a split second and its back to
this windows photo again. I also tried the settings you sent me above and no change.
I did notice one thing. When the computer idles and goes into slideshow and its stuck on that windows photo, if I press space bar or click to login and then don't log in and wait about 20 seconds, the clock and date magically appear and then the slideshow
starts. Once I hit space bar or click to login, it shows the login screen but the background is the windows photo and not one from the slideshow. Don't know if this helps.
Thanks,
Adam