Comment by KingMachiavelli

IMO bespoke containers using whatever python package manager makes sense for each project. Or make the leap to Nix(OS) and then still have to force every python project into compliance which can be very easy if the PyPy packages you need are already in the main Nix repo (nixpkgs) or very difficult if depends on a lot of uncommon packages, uses poetry, etc.

Since PEP 665 was rejected the Python ecosystem continues to lack a reasonable package manager and the lack of hashed based lock files prevents building on top of the current python project/package managers.