You could use swayidle and add a line to use either light or brightnessctl to dim and restore the brightness. Or just as I do turn off display after a certain time. This link should give you an idea. https://wiki.archlinux.org/title/Sway#Idle
Brightnessctl is installed and works just need a way to read whether is on ac or battery.
@JustineSmithies @rkk Should be able to read it from /sys/devices/ or with upower.
Are you running arch on the metal or through crostini/crouton? The second option probably will only respect chromeos' power management settings, but you may be able to flash a full uefi payload and get rid of chromeos completely with https://mrchromebox.tech/#fwscript
Yeah, i got all that (coreboot+arch)
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