Why does pip3 install in ~/.local on Debian?
The following warning in packaging.python.org may answer you questions
Warning Recent Debian/Ubuntu versions have modified pip to use the “User Scheme” by default, which is a significant behavior change that can be surprising to some users.
pip3 defaults to the user scheme when run outside virtual envs, and files are installed under
If you want to install a tool system-wide using
pip3 on Debian and derivatives, you can still use
pip3 install --system ...
to use the system scheme.
(It’s worth checking whether the tool in question is available as a Debian package; Debian 10 added many packages...)
As muru points out, virtual envs are a better approach in many cases. The whole topic of Python tool installation generates lots of discussion, even among core Python developers!