How to safely remove default folders? [duplicate]

Yes. See post #7 in your link.

Backup the config file (optional):

cp ~/.config/user-dirs.dirs ~/.config/user-dirs.dirs.bak

Edit the file by commenting out unnecessary entries:

vim ~/.config/user-dirs.dirs

Run update command:

xdg-user-dirs-update

DO NOT REMOVE XDG_DESKTOP_DIR