is there any way to override pinned dependencies of a third party pypi packages? There are many packages out there that just assumes we will have a small environment and pins all the dependencies. Rather than forking them or having to convince the author to relax the pinned version, it will be nice if we can have some control over them on our end

There is not. You must fork and switch to a `<project>@git+...`requirement to use your fork.

You could manually edit a lockfile I suppose?

You could, but then when the Pex runtime of a PEX built from that lock resolved what distributions to load it would say no.