It's not you. Python packaging has regressed into a worse mess than it was 20 years ago. I limit myself to simple scripts that only rely on builtins. Anything more complicated goes to a more dependable language.
e.g. poetry, venv and pyenv have been mentioned in just the next few comments below yours. and this is just one example. i have seen other such seeming confusion and different statements by different people about what package management approach to use for python.
I no longer shy away from writing <500 LOC utility/glue scripts in python thanks to uv.