Re-directed screenshot location via defaults file doesn't work
If you use sudo you change the default for the user you are sudoing into, in this case the root user. Just run the commands without sudo and you should be fine.

You can also clear any settings for a user with:

defaults delete com.apple.screencapture


You can test and log out if the system doesn’t realize the change was made. That’s usually better than killing the system UI server.