As of half a year ago with pip 25.1, it can install from "dependency groups" listed in pyproject.toml: https://ichard26.github.io/blog/2025/04/whats-new-in-pip-25....

Pip also generates PEP 751 lockfiles, and installing from those is on the roadmap still (https://github.com/pypa/pip/issues/13334).

venv is lower-level tooling. Literally all it does is create a virtual environment — the same kind that uv creates and manages. There's nothing to "integrate".