Edit: I just had to restart the computer - perhaps a login-logout would've sufficed for the udev rules to take effect? (brightnessctl adds some rules to allow non root users in the video and input groups to manipulate the necessary device, in my case intel_backlight.)

I'm on Artix with OpenRC on a Lenovo Thinkpad T480. I'm running dwm on X. I have successfully configured dwm's config.h - adding wpctl commands - to allow adjusting the volume with the F2 and F3 buttons. Works like a charm. Now, I am trying to do the same thing with brightnessctl, but whatever syntax I use, nothing happens. I have tried adding my user to the video and input groups, to no avail.

Should I chown or chmod the device under /sys/ to allow my user to manipulate, in my case, intel_backlight ? Or is there some other option?

brightnessctl works when used in the CLI no problem.