wallpaper not working in mac os sonoma

I've been using Apple OS systems for 20 years, and never had a problem with putting up wallpaper. Sonoma doesn't work. Please stop with useless workarounds and just fix it. You have dozen of OS's to look back at for excellent wallpaper accessibility.

Everytime I start up my mac mini, it opens with the wallpaper I want, then immediately stops and goes black for a second, then comes back with the Sonoma Horizon photo from Landscape on the screen (Landscape is not selected), and the Picture box is blank. So again I add a photo, and it holds that photo until I close the computer. Then the same thing the next day. I have tried many of the workarounds that I've found online, and none work. I don't want a workaround. As for the past 20 years, I want to select a photo (or whatever) and have that be my wallpaper, until I change it.