pip and venv are officially sanctioned. (venv and "ensure-pip" are included in python-3.x) That's all you really need (after you have the desired version of python).
If you use pip and requirements.txt, the dependency resolution is not great, it just installs things in order.
There isn't a lock file. How do you deal with dev dependencies? How do you work on a lib and its calling code without pushing it to pypa? Working with c deps?
All this stuff feels harder to do then it should be.
I have never used anything other than pip and venv. Maybe I'm missing something, but I never felt like I'm missing anything. And Python package management is so easy and simple if you stick to that (well, except version conflicts, but that's always a pain somehow).
