For narrative and color grading in Resolve, how well can the codec used by this cam be graded? How does it behave compared to Prores?

The codec will hold up well for adjusting contrast and adding saturation.

But no more than that?
So it's not really a cinema camera then?

What exactly are you looking to do with the footage in color correcting/grading it?

No more than being able to bring back some darker area, if necessary and have some latitude between the darker and brighter areas.

No more than being able to bring back some darker area, if necessary and have some latitude between the darker and brighter areas.

And that would be adjusting the contrast.