I think the correct link to the Stack Exchange post is - https://elementaryos.stackexchange.com/questions/18860/no-brightness-controls-after-fresh-install

Your link is not working.

Not sure why you're showing the Nightlight indicator. That's something else.
The power indicator menu with brightness control:

I'm assuming it won't show up for you there seeing it's not visible in the System Settings.

Mac OsX is a operating system. It tells us 0 about your hardware.

The nightlight wingpanel is also a kind of screen luminosity control, so i assumed Brightness controls share the same panel.
I used Juno for 2 days out of the box, but after looking thouroughly for brightness controls which i could not find, i tried to install some 3rd pary app to get some brightness control.
The beauty of Juno is its clean uncluttered interface. There is nothing confusing.

Secondly i thought…Maybe the battery panel is surpressed because my computer is not a laptop.

A relevant Stack Exchange question: https://elementaryos.stackexchange.com/questions/5465/how-to-reduce-the-brightness-of-a-desktop-pc
Another one for Ubuntu: https://askubuntu.com/questions/894465/changing-the-screen-brightness-of-the-external-screen

Looks like the power settings look for a file in /sys/class/backlight/, see:
https://github.com/elementary/switchboard-plug-power/blob/master/src/MainView.vala#L257-L277
Do you have something in /sys/class/backlight/?
It's not dependent, as far as I understand it on whether the computer is a laptop.

There is nothing inside /sys/class/backlight/
ok, i will create a file there, logout and report back
Sorry, what is the name of this file? MainView.vala ?

That's not how that works. You can't just add a file and have it work.

Please read for example: https://askubuntu.com/questions/894465/changing-the-screen-brightness-of-the-external-screen

I guess the question would be whether we can integrate Brightness Controller into the power settings, but then I wonder why even Ubuntu didn't do that.

indeed it does not work this way. I created the file in Downloads and tried to move it to dest directory. Access denied even with sudo

cd Downloads
sudo cp MainView.vala /sys/class/backlight/MainView.vala

Ahhh…i see
I already stumbled myself over this topic. Correcting brightness via shell command. Not really exciting, as for now i dont know how to code a snippet to which i could assign a shortcut

i read somewhere online that Ubuntu derivatives suffer from common problems, like the one controlling brightness adjustments. My battery preference is surpressed somehow, but this issue were there from day one on. Following the installer process, i noted that Juno had ignored various packages during its first install.

I configured nothing special in the Juno installer on my USB stick (then installing over my HD partition), except the reformatting of my Fat partition i had created before on my Mac, to a linux partition - ext4 to be exact.

should i see something useful in: systemctl list-units --type service ?
the only line with error is:
xpra.service loaded failed failed Xpra System Server
could not find anything related by searching for keywords like: battery, brightness or their like :(

another topic is to change kernel to get brightness back. Not sure if this is THE way to go for me
https://www.youtube.com/watch?v=yOmIldZYLFk