> This was always my issue with pip and venv: I don’t want a thing that hijacks my terminal and PATH ...

What's the "this" that is supposedly always your issue? Your comment is phrased as if you're agreeing with the parent comment but I think you actually have totally different requirements.

The parent comment wants a way to have Python packages on their computer that persist across projects, or don't even have a notion of projects. venv is ideal for that. You can make some "main" venv in your user directory, or a few different venvs (e.g. one for deep learning, one for GUIs, etc.), or however you like to organise it. Before making or running a script, you can activate whichever one you prefer and do exactly like parent commenter requested - make use of already-installed packages, or install new ones (just pip install) and they'll persist for other work. You can even switch back and forth between your venvs for the same script. Totally slapdash, because there's no formal record of which scripts need which packages but also no ceremony to making new code.

Whereas your requirements seem to be very project-based - that sounds to me like exactly the opposite point of view. Maybe I misunderstood you?