Mac OS Big Sur - Is there a way to change login wallpaper in Big Sur?

Question

I want to change the login glbt wallpaper. I don't mean the wallpaper after login. I want to erase, eliminate forever this image of ridiculous colors that remain in the login in Big Sur . Thanks for any help. I've try to change permission in /System/Library/Desktop Pictures with sudo, but nothing.

Answer 1

I downloaded a 3rd party desktop image and used it as my desktop. Go to system Preferences and click on the Desktop and Screensaver option. When this opens go to desktop and define your new image. My login screen is now gray. I used a solid black screen image with a white apple logo. I'm pretty sure thats all i did.