> I don’t want a thing that hijacks my terminal and PATH
The shame is ... it never had to be that way. A venv is just a directory with a pyvenv.cfg, symlinks to an interpreter in bin, and a site-packages directory in lib. Running anything with venv/bin/python _is_ running in the virtual environment. Pip operations in the venv are just venv/bin/python -m pip ... . All the source/deactivate/shell nonsense obfuscating that reality did a disservice to a generation of python programmers.
> The shame is ... it never had to be that way.
It isn't that way. Nothing is preventing you from running the venv's python executable directly.
But the original designer of the concept appears to have thought that activation was a useful abstraction. Setting environment variables certainly does a lot to create the feeling of being "in" the virtual environment.