Slow wallpaper downloads and disappearance after macos updates on macbook

I’m on Version 15.6.1 (24G90), and downloading wallpapers takes an unusually long time. This isn’t due to my internet speed, as it happens even with a fast connection. What’s even more frustrating is that every time the system updates, all previously downloaded wallpapers disappear. A proper fix for this is long overdue.

[Re-Titled by Moderator]

Original Title: Wallpaper Issue