The M3 Pro and Max get virtually identical results in battery tests, e.g. https://www.tomsguide.com/news/macbook-pro-m3-and-m3-max-bat.... The Pro may be a perfectly fine machine, but Apple didn't remove cores to increase battery life; they did it to lower costs and upsell the Max.
In all M generations, the max and pro are effectively different layouts so can’t be put down to binning. Each generation did offer binned versions of the Pro and Max with fewer cores though.
