[civodul]

Guix channels (not to be confused with Nix channels) let you turn a Git repo into a package collection:

https://guix.gnu.org/manual/devel/en/html_node/Channels.html

I guess it serves some of the same purposes as Flakes, and it comes with other bells and whistles such as authentication (which I think is kinda important!).

For the rest, your description of Guix is largely incorrect ("has none of that", "you have to roll back the complete Guix system", etc.), but as a Guix hacker I'd be interested in better understanding your experience and perceptions if you'd like to get in touch with us on the mailing lists!