rafaeldrumond

If someone wanted to build, let's say, an Arduino dial to adjust the color sliders for example. Where would one had too look or read to make such device/plugin?

I play around using Affinity Photo to develop some RAW files, just to see how it performs. I also don't use DPP much at all, however it will give you the most accurate results. I use Lightroom to develop my RAW files. If there's further processing, like removing objects, or stylizing, I'll use Affinity Photo for that.  Unless you have Exposure Bias and Tone Curve checked in the Develop Assistant, a RAW file will appear flat. You can try switching them on and see if that's where you want to start.
There is a customer beta of the next update available. You might try it and see if you get better results. Affinity Customer Beta 1.7 for Windows
 

Customer beta, not a public beta.
It will only run if one has purchased an earlier version of Photo. (A public beta, like for Publisher, doesn't require any prior purchase.)

Oops, corrected it in my post. Thanks Walt.