help: guix mate desktop issue

[dikasp]

Hi newbie here, im just installed guixsd mate desktop with following
problem:

1. mate power manager always ask authentication when brightness changed,
even when it dim the screen on its own.

2. i cant fix screen flickering, usualy in archlinux im just create config
file /etc/X11/xorg.conf.d/20-intel.conf but in guix it seems not recognised
by the system.

many thanks in advance.