Before I explain this, I am running Windows 11, but this also happens on Windows 10. I tested this on 2 different computers, so it seems like this issue is easily repeatable.
If you try to change your wallpaper to a really big picture (the one that I was trying to use is 39.4 MB, resolution 7680x4320), it will change your background to a solid color, and the settings app will freeze. Along with this, your settings app will then become very slow to use after attempting to do this until you restart your computer.
I will attach the picture that I was using for others to test. I asked people in a discord server if they were having the same issue attaching this photo and they all experienced the same thing. Seems like Windows freaks out when you try to change your wallpaper to this or other images to a similar scale.