Ah, you’re teetering on the edge of the ‘rabbit hole’. You want what I wanted three years ago, and it took a lot of study and experimentation to even understand what that means, and I’m still not where I want to be.
For what it’s worth, I’d recommend you put aside DCPs for a bit; they offer significant capability that is hard to comprehend straight-away.
I wrote a missive about this a few months ago, necking down the essentials of managing color in raw processing:
It’s ICC-oriented, but it’s there that the essential dynamic of managing color is best understood to start.
The camera primaries in dcraw’s adobe_coeff table and RT’s camconst.json are actually cam->XYZ matrices, anchored to a D65 white point. In dcraw, inverses are calculated and used for various purposes, but the essential transform that gets you to a pleasing rendition of your image is cam → XYZ → output, where output=sRGB|Adobe|ProPhoto|etc. You could use dcraw to deliver 16-bit TIFFs in linear ProPhoto, and they’d be quite nice for your purposes.
Well, until you start to deal with extreme colors. Cameras capture light in gradations that produce colors well beyond our ability to comprehend, and that range eventually has to be crushed to something that can be accommodated by limited displays or printers. To keep some gradation in extreme colors, these transforms need to be augmented with behaviors that make more nuanced decisions about what lesser color each rich color gets transformed to. Anders Torger’s dcamprof page describes a lot of this quite well.
There’s one more reading I commend, one that’ll help both with understanding the essentials of color management as well as the more general endeavor of raw processing:
@Elle Stone used to post here, but her expansive writings live on to shape our heads in righteous ways…