After almost 2 months of reading about DDC/CI and how I can use it to send commands to external monitors, I finally got Lunar 0.1 semi-working.
I was calling it AdaptiveService or Adaptivo then. I had no plans to publish it as a full-fledged app, but I published the code on Github anyway in case others might be in need of inspiration for their project.
I couldn't have done Lunar without another Github project that is still at the base of it and all other monitor controlling apps in existence now: https://github.com/kfix/ddcctl