I tried "shady fo mac" before. The issue I had with it was that it only shaded the desktop, not the virtual desktops of maximized apps.
Then, I tried QuickShade, this one covered virtual desktops and it supported keyboard shortcut to increase/decrease light; well not exactly brightness, since it was on OLED screen. It just shaded the color which I guess is equivalent to brightness control in OLED. The problem: When you switched between desktop, for a moment, the brightness goes up, which was very annoying.
At the end, I purchased NightTone from app store for $2.99. Here are the pros and cons:
Pros:
* Support virtual desktops
* Does not flicker on switching screen
Cons:
* No keyboard control shortcut
* limited brightness levels.
* Not free
I'm not sure if this forum allows promoting paid apps, if so, please let me know. My experience was that $2.99 was worth a better brightness control that doesn't jump.
Anyway, I returned the OLED screen laptop and I went for one with LCD, now the keyboard keys adjust the brightness but I miss the vibrancy and sharpness of OLED.
Hope this was usefull.