We are well aware of the challenges. Read a bit into the documentation and the efforts that has gone into achieving reproducible builds on different distributions.
This is hard on distributions as we are suppose to support all the ecosystems. But for rubygems, pypi, go, rust, npm and so on this is a easier problem to solve if they want to. But even with all these challenges, Debian is at 94% reproducible packages, and Arch is edging closer to 80%.
Introducing non-determinism into your build process is something that should be removed, and all ecosystems should be aligned in this effort.
Weekly blog posts are written about the current efforts.
https://reproducible-builds.org/blog/
