Hi and welcome to Arturia forums.
You have many and also better possibilities, than you think now, it look like.
You talk about some reserved midi CC's.
Beside those Pigments do have a Midi learn function. It's a midi connector icon at the top right of the application. When enabled you can assign any control you click on, when you see a dialog window. Please consult the manual about midi learn.
I can also suggest, that you assign your controller to Pigments macros and modulators. That way you can control multiple parameters at a time, and not just a single cutoff for a single filter, which in many cases will not give you the desired change in sound.
Keep in mind, that Pigments have multiple filters.
You have a lot of control possibilities, that you clearly can't even imagine by now. You'll find out, when you learn about Pigments.
Learn about modulation, modulators and the sidechain possibilities. You can do very expressive modulation.
I can add, that you also can create different midi configurations. Please consult the manual about that too.