> This same tutorial cites pip-tools, hatch, poetry. Does that mean that they “endorse” these tools as well?

Those tools are relegated to a small section at the end, whereas the main body of the text says "Pipenv is recommended for collaborative projects..."

I'd say that counts as a specific endorsement of Pipenv. I guess it's an endorsement by the "Python Packaging Authority" rather than "Python Core" but it's pretty hard for someone at the tutorial-reading level to perceive the difference.