Control the brightness of your screen in CLI, or define shortcuts.
Script dcc-brightness is a convenient wrapper around ddcutil (doc, source).
As the later can be quite slow, we rely on a cache file to speed things up: /tmp/dcc.cache.
Install ddcutil.
Put file dcc-brightness somewhere in your path (e.g. /usr/local/bin, ~/.local/bin or ~/bin) and make it executable.
Lower the brightness value by 10:
dcc-brightness --delta -10
Increase the brightness value by 10:
dcc-brightness --delta 10
Set the brightness value to 50:
dcc-brightness --set 10