But that's not the recommended way to install pypi packages you want to use, with debian at least. This may install dependencies that will break (for your user) some debian packages depending on other versions of said dependencies. The easy way to go is `pipx install west`.
EDIT: --user is not necessary anymore. I think this does not alter the validity of the rest of my comment.
Does it try to install packages in your system paths and fails due to lack of permissions?
Anyway, I think this does not change the fact that it's a bad idea to populate your ~/.local/lib with python libs, since it may break some python programs installed via apt for your user, or was that wrong too?
As to filling your lib with stuff, it depends. AFAICR the default is to search for things there first, because it is assumed the user environment takes precedence.
pip —user
It’s a bad idea right up there with Linux distros having python2, python3, python3.1, puthon3.2, python3.3, …. They give up the ease of use of a command line application where you can tell people what to type for the mind numbing complexity of a GUI application where it takes a 1500 page book to explain how to do anything in Microsoft Word because now you can’t tell people what to type to run and install things.