Guix on a foreign distro (Mint) - List of packages is outdated and not updatable

[MutoShack]

I've been using Guix for a while on my Mint 19.1 machine. When Nano 4.0
came out as a Guix package I was excited, so I ran:
'guix pull && guix package -u'
on my machine. It pulled Nano 2.9.3 from mirror.hydra.gnu.org (I
recently had Nano 3.4 installed, which means Guix downgraded my package)

My laptop computer, running GuixSD, pulled Nano 4.0 (and other new packages) 
perfectly fine.

Running
'/path/to/guix-daemon --substitute-urls="https://ci.guix.info";'
and pulling yields the same result.
Deleting '~/.config' on both user & root, then letting 'guix pull'
regenerate them also did nothing.

I tried changing my generation and deleting old generations.
I tried the good old "RTFM" and "STFW" methods (reading info and
websearching), but I could not find an answer. Maybe I misunderstood the
information I found.