Ah, I see, thanks for your response! At PyBay I saw something similar to pex called
fromager. It rebuilds complete dependency trees of Python wheels from source, so I guess it's kinda like an sdist pex. Seemed interesting for more secure requirements. The presenter made the point that with the influx of AI generated code, an increasing number of PyPI artifacts are compromised so building from source is going to be more and more important.