Missing /usr/local/sbin directory in the /etc/paths file
The /usr/local/sbin directory does not exist on a default macOS installation, but you can easily add it yourself.

To add that directory to the system-wide PATH environment variable (for all users), as there is always the risk of a macOS update overwriting /etc/paths, it might be better to add a file named usr_local_sbin (or anything else) to /etc/paths.d with that single line:

/usr/local/sbin


This will put the /usr/local/sbin path in a position close to the end of PATH, which usually (assuming unique command names) is not a problem. If you want to have it early in PATH for whatever reason, either add to  /etc/paths nevertheless or edit the PATH order in the user-specific ~/.profile.