As Kovid said, if you use the binary installer it's more complicated to add additional modules. But also if you're going to use the [community] package then you might as well also use
https://www.archlinux.org/packages/c...y/python-pudb/
Don't ever use pipx. Pipx is intended for creating one virtualenv for each module you install, the virtualenv contains copies of every dependent module and in order to add the library path you need to run the module using pipx.
It's an unwisely created piece of software which is basically "docker for python" and it doesn't interoperate with anything else anywhere ever.
"pip install pudb" would work fine, by default pip does a local user install (as if you specified pip install --user pudb) for precisely the issue of you should not need root for this.
Note that for the distro binaries rather than the official prebuilt binaries, you will want to override the source code using "export CALIBRE_PYTHON_PATH" rather than CALIBRE_DEVELOP_FROM.