New macOS install "missing commands" but commands already exist in /usr/bin
This is normal: Certain commands on macOS are installed as placeholders so that when you run them they can be installed, rather than simply saying the command was not found.
The command will work as expected now, there won't be a noticeable difference except that technically there is a wrapping layer that calls the actual executable.
You should not worry, this is the same for all installs. You can proceed to install brew.