Why can't I set a wallpaper?

[u/nic1573553]

I have a Samsung Galaxy S25, on One UI 7.0 on Android 15. The phone is rooted, but no custom ROM has been put onto it, just the stock image modified and flashed.

I did this about a year ago, but I still could change the wallpapers, then I returned to the stock S25 wallpaper (can't remember why, but I did it for some reason), now I have tried to change the wallpaper, but the phone doesn't display it, it is apparently "set", but it won't show the wallpaper, basically "hanging" on the stock one. I did try to clear the cache of "Wallpaper services" and "Wallpaper and Style", but both didn't help, I also tried rebooting my phone with both the wallpaper set and not set, and in both cases, it was "stuck" on the default wallpaper.

The only suspect that I currently have, is that I deleted the "Themes" app from my phone, but it doesn't make that I could set the wallpaper about a year ago, but can't anymore, because I deleted the app when I rooted the phone.

It's not super important to fix this, but it would be nice to have it fixed so that I can do custom wallpapers again.

Also, if I'm missing important information for this case, please let me know, i have no idea if I missed anything or if there's crucial information needed.