exwm not resizing properly

[at e]

Hello, emacs users. Hopefully this mailing list is the
right place for this question, or someone can direct
me to where I can get assistance.

I've been using emacs X window manager
(found at https://github.com/ch11ng/exwm) for
a while now, and it works excellently with Gentoo.
However, I've been transitioning over to GuixSD,
and am now having problems with exwm resizing
properly.

Specifically, while exwm starts (from the slim display
manager), it only takes up part of the upper-left corner
of the screen. When I run exwm in Gentoo, I can see
a process where exwm resizes its frame to fill the
screen. This process also occurs on GuixSD, but the
frame only resizes to a small part of the screen.

When I installed exwm on GuixSD, I had to manually install
a few components to get things working:
xhost
xset
xsetroot
gnome-settings-daemon
dbus
My guess is that I've missed a dependency somewhere.

Any ideas? Thanks.