Maybe PEX wants to join? https://packaging-con.org/

Or scie for that matter

Neither of those are package managers though

many different approaches to package management at the conference.

I think use "self-contained fat binaries" is an approach to package management, at least for the "shipping to end-users/prod" part of packaging

I read their topics as dealing with the pip side of things, not the deployment side of things, but maybe they are open to those topics too

As far as use goes, PEX is equivalent to an rpm, deb, or other packaging “format”, but it is a distro-agnostic packaging system.