I apologize for posting repeatedly. I think I succeeded in installing numpy and other libraries as well.
In case for someone in same situation, I would like to share my own case resolution.

After installing pip, not from c4dpy, but using the python below worked:
/Applications/Maxon Cinema 4D 2024/resource/modules/python/libs/python311.macos.framework/python

and executed the command like python -m pip install numpy normally.
And worked inside C4D properly.

If there are any inaccuracies or clear errors, I would appreciate it if you could point them out. Thank you in advance.

I apologize for posting repeatedly. I think I succeeded in installing numpy and other libraries as well.
In case for someone in same situation, I would like to share my own case resolution.

After installing pip, not from c4dpy, but using the python below worked:
/Applications/Maxon Cinema 4D 2024/resource/modules/python/libs/python311.macos.framework/python

and executed the command like python -m pip install numpy normally.
And worked inside C4D properly.

If there are any inaccuracies or clear errors, I would appreciate it if you could point them out. Thank you in advance.

I made a little progress and succeeded installing pip, by setting permissions with chmod to /Applications/Maxon Cinema 4D 2024/resource/modules and c4dpy itself, and using downloaded "get-pip.py" instead.
But I can't still install numpy yet...

c4dpy -m pip install numpy
sysctl: No such file or directory
Collecting numpy
  Using cached numpy-1.26.2-cp311-cp311-macosx_11_0_arm64.whl.metadata (115 kB)
Using cached numpy-1.26.2-cp311-cp311-macosx_11_0_arm64.whl (14.0 MB)
Installing collected packages: numpy
ERROR: Could not install packages due to an OSError: [Errno 13] Permission denied: 'lib'
Check the permissions.

I wish I could run the command with "sudo", but c4dpy Authentication Error appears...

sudo c4dpy -m pip install numpy
Error running authentication: Please sign into the Maxon App [license_maxonapp.cpp(689)]
Open the ApplicationManager to assign a license: mxapp://localhost/open/v1?source=net.maxon.cinema4d.cmdline&version=2024.000
Please fix the license in the MaxonApp, press return to try again:

I think c4dpy is already authenticated, and the license is assigned to C4D 2024 in Maxon App, which is opened from the link.

Is there anything I can try in this situation?
Thank you.

@m_adam Hi Maxime.
Sorry for cutting in. I followed these instructions, and c4dpy authentication seems OK.
But "c4dpy -m ensure pip" always give me errors, and I can't import numpy.
Is there anything I can do after this?

/Applications/Maxon\ Cinema\ 4D\ 2024/c4dpy.app/Contents/MacOS/c4dpy -m ensurepip
sysctl: No such file or directory
sysctl: No such file or directory
/Applications/Maxon Cinema 4D 2024/c4dpy.app/Contents/MacOS/c4dpy: can't open file 'ignore::DeprecationWarning': no such file or directory (file:///Applications/Maxon Cinema 4D 2024/resource/modules/volumes/libs/macOS_universal/ignore::DeprecationWarning)
(null)Traceback (most recent call last):
(null)  File "<frozen runpy>", line 198, in _run_module_as_main
(null)  File "<frozen runpy>", line 88, in _run_code
(null)  File "/Applications/Maxon Cinema 4D 2024/resource/modules/python/libs/python311.macos.framework/lib/python3.11/ensurepip/__main__.py", line 5, in <module>
(null)    sys.exit(ensurepip._main())
(null)             ^^^^^^^^^^^^^^^^^
(null)  File "/Applications/Maxon Cinema 4D 2024/resource/modules/python/libs/python311.macos.framework/lib/python3.11/ensurepip/__init__.py", line 286, in _main
(null)    return _bootstrap(
(null)           ^^^^^^^^^^^
(null)  File "/Applications/Maxon Cinema 4D 2024/resource/modules/python/libs/python311.macos.framework/lib/python3.11/ensurepip/__init__.py", line 202, in _bootstrap
(null)    return _run_pip([*args, *_PACKAGE_NAMES], additional_paths)
(null)           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(null)  File "/Applications/Maxon Cinema 4D 2024/resource/modules/python/libs/python311.macos.framework/lib/python3.11/ensurepip/__init__.py", line 103, in _run_pip
(null)    return subprocess.run(cmd, check=True).returncode
(null)           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(null)  File "/Applications/Maxon Cinema 4D 2024/resource/modules/python/libs/python311.macos.framework/lib/python3.11/subprocess.py", line 571, in run
(null)    raise CalledProcessError(retcode, process.args,
(null)subprocess.CalledProcessError: Command '['/Applications/Maxon Cinema 4D 2024/c4dpy.app/Contents/MacOS/c4dpy', '-W', 'ignore::DeprecationWarning', '-c', '\nimport runpy\nimport sys\nsys.path = [\'/var/folders/wg/w0xrgt954qz99qpz4tg69bf40000gn/T/tmplj1265bd/setuptools-65.5.0-py3-none-any.whl\', \'/var/folders/wg/w0xrgt954qz99qpz4tg69bf40000gn/T/tmplj1265bd/pip-23.1.2-py3-none-any.whl\'] + sys.path\nsys.argv[1:] = [\'install\', \'--no-cache-dir\', \'--no-index\', \'--find-links\', \'/var/folders/wg/w0xrgt954qz99qpz4tg69bf40000gn/T/tmplj1265bd\', \'setuptools\', \'pip\']\nrunpy.run_module("pip", run_name="__main__", alter_sys=True)\n']' returned non-zero exit status 2.