Wallpaper on iMac not doing what it should! 15.1.1

I've chosen an album from photos that I'd like my wallpaper to cycle through randomly.

On first try, the wallpaper just reverts to 'sequoia sunrise', even though my album is selected.

I've looked up some hints online, and if I then click on 'see more' from my album and start clicking on photos, then the ones I've clicked on quickly say 'downloading' and then will appear as my wallpaper, and when I click on random again, only the photos I clicked on appear in the cycle.

Thing is, I have over 800 photos in that album, and I don't want to have to click on each one of them and 'download' them so that they play as wallpaper.

Anyhow, whenever I log out or shut down, the wallpaper reverts back to 'sequoia sunrise' again, and I have to start the whole process again.

Why is something this simple so buggy??? What's the big deal?

I was thinking that maybe photos keeps pushing them to the cloud and therefore can't use them in wallpaper. I tried to find if there was a way to keep all the photos permanently on the computer, but you have to either do it with all photos or none, you can't choose specific albums.

I might try making a folder NOT on the cloud and seeing if that will run as wallpaper.

I will report back. But in the mean time, PLEASE FIX THIS!!

Thank you kindly.