It would be nice for the ability to control the brightness screen dimming. Maybe a setting in display settings so it can be on a per display basis. It would be nice for it to be a slider for different use cases.
OLED displays would benefit from almost minimum brightness at idle. Displays on old laptops would benefit from a conservative dimming for example in use cases where its desirable but only to the extent where it’s still legible.
My OLED monitor behaves like a KVM but when the screen goes off it turns off the speaker output. When I put it into presentation mode it would be nice to have it dim aggressively after a few minutes instead of using something like allblackscreens.com or a black image.
#SaveTheOLEDs 
I use a laptop that has a OLED screen for audio uses in my bedroom. Currently when I boot it up, I ssh to it and run:
systemctl --user restart wireplumber\* pipewire\*
sudo brightnessctl s 0
I do the former command because I’m not logging into the desktop so without starting pipewire and wireplumber I wouldn’t have the audio services. The sudo brightnessctl s 0 sets my OLED to off since I don’t need it for simply playing audio to my usb dac
My user account has “linger” set to yes and I’m in the ‘audio’ group
I don’t have that luxury sadly, my speakers are plugged into my monitor so both my laptop and desktop can use it and the brightness control is done via plasma’s software implementation.
The hardware implementation seemed to be dropped due to edge cases bugs. My laptop plays audio through its speakers when the monitor goes to sleep but my desktop doesn’t have that capability(excluding headphones). It’s just a choice the monitor manufacturer made to save power I guess.