Multishot capture* has no bearing on overall Color Accuracy. None.
You actually have to try pretty hard to create the niche conditions where multishot has any impact on color at all; you need a strongly saturated subject whose color changes sharply on a per pixel basis; for example, think of shooting a table full of marbles from such a height that each marble was exactly one pixel in size.
I think a lot misunderstanding from this topic comes from history. Hasselblad and Sinar, to their credit, have cared about neutral color reproduction for a long time and both companies also made multishot backs, so “multishot” and “Color accuracy” were conflated in the minds of users. Phase One only really started focusing on the minutia of Color accuracy (eg museums and libraries) in the last decade. In my (biased) option they have taken the lead during that time as evidenced by Capture One CH edition, the Trichromatic, and their very long list of Museum and Library clients.
Multishot CAN improve resolution, assuming lens, aperture, focus, subject flatness and other factors like vibration are very tightly controlled. The other generally accepted method to do so is to stitch the subject in multiple captures. Both techniques have their pros and cons, though in my biased opinion, the option to move the camera or subject rather than sensor becomes preferential for practical reasons once you’re in the 60-80mp range.
*here I mean the type of multishot capture where you move the sensor
