What I usually do is make a venv using pip, then use that venv to install poetry in it, because I don't want to clutter my system with outdated poetry package. Then use Poetry to install packages inside the venv. So the pip part is merely for bootstrapping.
You shouldn't have to launch a sub-shell to run a script interpreter. That is exemplary of how nobody in the Python leadership can fix their perpetual packaging f-ups of the last two decades and are now just sticking their collective heads in the sand.
